initial commit

78 files changed, 3505 insertions, 0 deletions

diff --git a/src/skaembutils/deps-exe/s6-basename b/src/skaembutils/deps-exe/s6-basename
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-basename
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-cat b/src/skaembutils/deps-exe/s6-cat
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-cat
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-chmod b/src/skaembutils/deps-exe/s6-chmod
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-chmod
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-chown b/src/skaembutils/deps-exe/s6-chown
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-chown
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-clock b/src/skaembutils/deps-exe/s6-clock
new file mode 100644
index 0000000..a11a5f4
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-clock
@@ -0,0 +1,2 @@
+-lskarnet
+${SYSCLOCK_LIB}
diff --git a/src/skaembutils/deps-exe/s6-cut b/src/skaembutils/deps-exe/s6-cut
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-cut
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-dirname b/src/skaembutils/deps-exe/s6-dirname
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-dirname
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-echo b/src/skaembutils/deps-exe/s6-echo
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-echo
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-env b/src/skaembutils/deps-exe/s6-env
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-env
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-expr b/src/skaembutils/deps-exe/s6-expr
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-expr
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-false b/src/skaembutils/deps-exe/s6-false
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-false
diff --git a/src/skaembutils/deps-exe/s6-format-filter b/src/skaembutils/deps-exe/s6-format-filter
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-format-filter
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-grep b/src/skaembutils/deps-exe/s6-grep
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-grep
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-head b/src/skaembutils/deps-exe/s6-head
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-head
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-linkname b/src/skaembutils/deps-exe/s6-linkname
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-linkname
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-ln b/src/skaembutils/deps-exe/s6-ln
new file mode 100644
index 0000000..e027835
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-ln
@@ -0,0 +1,3 @@
+-lskarnet
+${SOCKET_LIB}
+${TAINNOW_LIB}
diff --git a/src/skaembutils/deps-exe/s6-ls b/src/skaembutils/deps-exe/s6-ls
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-ls
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-maximumtime b/src/skaembutils/deps-exe/s6-maximumtime
new file mode 100644
index 0000000..1840bc1
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-maximumtime
@@ -0,0 +1,2 @@
+-lskarnet
+${TAINNOW_LIB}
diff --git a/src/skaembutils/deps-exe/s6-mkdir b/src/skaembutils/deps-exe/s6-mkdir
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-mkdir
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-mkfifo b/src/skaembutils/deps-exe/s6-mkfifo
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-mkfifo
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-nice b/src/skaembutils/deps-exe/s6-nice
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-nice
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-nuke b/src/skaembutils/deps-exe/s6-nuke
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-nuke
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-pause b/src/skaembutils/deps-exe/s6-pause
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-pause
diff --git a/src/skaembutils/deps-exe/s6-printenv b/src/skaembutils/deps-exe/s6-printenv
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-printenv
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-quote b/src/skaembutils/deps-exe/s6-quote
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-quote
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-quote-filter b/src/skaembutils/deps-exe/s6-quote-filter
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-quote-filter
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-rename b/src/skaembutils/deps-exe/s6-rename
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-rename
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-rmrf b/src/skaembutils/deps-exe/s6-rmrf
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-rmrf
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-sleep b/src/skaembutils/deps-exe/s6-sleep
new file mode 100644
index 0000000..1840bc1
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-sleep
@@ -0,0 +1,2 @@
+-lskarnet
+${TAINNOW_LIB}
diff --git a/src/skaembutils/deps-exe/s6-sort b/src/skaembutils/deps-exe/s6-sort
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-sort
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-sync b/src/skaembutils/deps-exe/s6-sync
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-sync
diff --git a/src/skaembutils/deps-exe/s6-tail b/src/skaembutils/deps-exe/s6-tail
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-tail
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-test b/src/skaembutils/deps-exe/s6-test
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-test
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-touch b/src/skaembutils/deps-exe/s6-touch
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-touch
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-true b/src/skaembutils/deps-exe/s6-true
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-true
diff --git a/src/skaembutils/deps-exe/s6-uniquename b/src/skaembutils/deps-exe/s6-uniquename
new file mode 100644
index 0000000..e027835
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-uniquename
@@ -0,0 +1,3 @@
+-lskarnet
+${SOCKET_LIB}
+${TAINNOW_LIB}
diff --git a/src/skaembutils/deps-exe/s6-unquote b/src/skaembutils/deps-exe/s6-unquote
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-unquote
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-unquote-filter b/src/skaembutils/deps-exe/s6-unquote-filter
new file mode 100644
index 0000000..e7187fe
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-unquote-filter
@@ -0,0 +1 @@
+-lskarnet
diff --git a/src/skaembutils/deps-exe/s6-update-symlinks b/src/skaembutils/deps-exe/s6-update-symlinks
new file mode 100644
index 0000000..e027835
--- /dev/null
+++ b/src/skaembutils/deps-exe/s6-update-symlinks
@@ -0,0 +1,3 @@
+-lskarnet
+${SOCKET_LIB}
+${TAINNOW_LIB}
diff --git a/src/skaembutils/s6-basename.c b/src/skaembutils/s6-basename.c
new file mode 100644
index 0000000..113e14b
--- /dev/null
+++ b/src/skaembutils/s6-basename.c
@@ -0,0 +1,45 @@
+/* ISC license. */
+
+#include <skalibs/sgetopt.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-basename [ -n ] file [ suffix ]"
+
+int main (int argc, char const *const *argv)
+{
+  stralloc sa = STRALLOC_ZERO ;
+  int nl = 1 ;
+  PROG = "s6-basename" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "n", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n' : nl = 0 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  if (!sabasename(&sa, argv[0], str_len(argv[0])))
+    strerr_diefu2sys(111, "get basename of ", argv[0]) ;
+  if (argc >= 2)
+  {
+    unsigned int n = str_len(argv[1]) ;
+    if ((n < sa.len) && !byte_diff(argv[1], n, sa.s + sa.len - n))
+      sa.len -= n ;
+  }
+  if (nl && !stralloc_catb(&sa, "\n", 1))
+    strerr_diefu2sys(111, "get basename of ", argv[0]) ;
+  if (allwrite(1, sa.s, sa.len) < sa.len)
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-cat.c b/src/skaembutils/s6-cat.c
new file mode 100644
index 0000000..f0166be
--- /dev/null
+++ b/src/skaembutils/s6-cat.c
@@ -0,0 +1,12 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+int main (void)
+{
+  PROG = "s6-cat" ;
+  if (fd_cat(0, 1) < 0) strerr_diefu1sys(111, "fd_cat") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-chmod.c b/src/skaembutils/s6-chmod.c
new file mode 100644
index 0000000..9cf6f80
--- /dev/null
+++ b/src/skaembutils/s6-chmod.c
@@ -0,0 +1,34 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+
+#define USAGE "s6-chmod mode file"
+
+int main (int argc, char const *const *argv)
+{
+  mode_t mode = 0 ;
+  unsigned int m ;
+  PROG = "s6-chmod" ;
+  if (argc < 3) strerr_dieusage(100, USAGE) ;
+  if (!uint0_oscan(argv[1], &m)) strerr_dieusage(100, USAGE) ;
+
+  if (m & 0001) mode |= S_IXOTH ;
+  if (m & 0002) mode |= S_IWOTH ;
+  if (m & 0004) mode |= S_IROTH ;
+  if (m & 0010) mode |= S_IXGRP ;
+  if (m & 0020) mode |= S_IWGRP ;
+  if (m & 0040) mode |= S_IRGRP ;
+  if (m & 0100) mode |= S_IXUSR ;
+  if (m & 0200) mode |= S_IWUSR ;
+  if (m & 0400) mode |= S_IRUSR ;
+  if (m & 01000) mode |= S_ISVTX ;
+  if (m & 02000) mode |= S_ISGID ;
+  if (m & 04000) mode |= S_ISUID ;
+
+  if (chmod(argv[2], mode) == -1)
+    strerr_diefu2sys(111, "change mode of ", argv[2]) ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-chown.c b/src/skaembutils/s6-chown.c
new file mode 100644
index 0000000..ef6a4a0
--- /dev/null
+++ b/src/skaembutils/s6-chown.c
@@ -0,0 +1,60 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-chown [ -U ] [ -u uid ] [ -g gid ] file"
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  int uid = -1, gid = -1 ;
+  PROG = "s6-chown" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "Uu:g:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'u':
+        {
+          unsigned int u ;
+          if (!uint0_scan(l.arg, &u)) strerr_dieusage(100, USAGE) ;
+          uid = u ;
+          break ;
+        }
+        case 'g':
+        {
+          unsigned int g ;
+          if (!uint0_scan(l.arg, &g)) strerr_dieusage(100, USAGE) ;
+          gid = g ;
+          break ;
+        }
+        case 'U':
+        {
+          unsigned int x ;
+          char const *s = env_get2(envp, "UID") ;
+          if (!s) strerr_dienotset(100, "UID") ;
+          if (!uint0_scan(s, &x)) strerr_dieinvalid(100, "UID") ;
+          uid = x ;
+          s = env_get2(envp, "GID") ;
+          if (!s) strerr_dienotset(100, "GID") ;
+          if (!uint0_scan(s, &x)) strerr_dieinvalid(100, "GID") ;
+          gid = x ;
+          break ;
+        }
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  if (chown(*argv, uid, gid) == -1)
+    strerr_diefu2sys(111, "chown ", argv[0]) ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-clock.c b/src/skaembutils/s6-clock.c
new file mode 100644
index 0000000..822500a
--- /dev/null
+++ b/src/skaembutils/s6-clock.c
@@ -0,0 +1,31 @@
+/* ISC license. */
+
+#include <skalibs/allreadwrite.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/tai.h>
+
+#define USAGE "s6-clock [ tai64nlabel ]"
+
+static int getit (void)
+{
+  char fmt[TIMESTAMP+1] ;
+  timestamp(fmt) ;
+  fmt[TIMESTAMP] = '\n' ;
+  if (allwrite(1, fmt, TIMESTAMP+1) < TIMESTAMP+1)
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
+
+static int setit (char const *h)
+{
+  tain_t a ;
+  if (!timestamp_scan(h, &a)) strerr_dieusage(100, USAGE) ;
+  if (!tain_setnow(&a)) strerr_diefu1sys(111, "taia_setnow") ;
+  return 0 ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  PROG = "s6-clock" ;
+  return (argc < 2) ? getit() : setit(argv[1]) ;
+}
diff --git a/src/skaembutils/s6-cut.c b/src/skaembutils/s6-cut.c
new file mode 100644
index 0000000..bb729d0
--- /dev/null
+++ b/src/skaembutils/s6-cut.c
@@ -0,0 +1,212 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/diuint.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/genalloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-cut [ -b list | -c list | -f list ] [ -d delim ] [ -n ] [ -s ] [ file... ]"
+
+static int diuint_cmpleft (void const *a, void const *b)
+{
+  return ((diuint const *)a)->left - ((diuint const *)b)->left ;
+}
+
+static void diuintalloc_normalize (genalloc *list)
+{
+  unsigned int i = 1, cur = 0 ;
+  unsigned int len = genalloc_len(diuint, list) ;
+  register diuint *const s = genalloc_s(diuint, list) ;
+  qsort(s, len, sizeof(diuint), &diuint_cmpleft) ;
+  for (; i < len ; i++)
+    if (!s[cur].right) break ;
+    else if (s[i].left > s[cur].right) s[++cur] = s[i] ;
+    else if (s[cur].right < s[i].right)
+      s[cur].right = s[i].right ;
+  genalloc_setlen(diuint, list, cur+1) ;
+}
+
+static void scanlist (genalloc *list, char const *s)
+{
+  register unsigned int i = 0 ;
+  genalloc_setlen(diuint, list, 0) ;
+  while (s[i])
+  {
+    char const sep[4] = ", \t" ;
+    diuint iv ;
+    if (s[i] == '-') iv.left = 1 ;
+    else
+    {
+      unsigned int j = uint_scan(s+i, &iv.left) ;
+      if (!j || !iv.left) strerr_dief2x(100, "invalid list argument: ", s) ;
+      i += j ;
+    }
+    if (s[i] != '-') iv.right = iv.left ;
+    else
+    {
+      unsigned int j = uint_scan(s + ++i, &iv.right) ;
+      if (!j) iv.right = 0 ;
+      else if (iv.right < iv.left)
+        strerr_dief2x(100, "invalid list argument: ", s) ;
+      else i += j ;
+    }
+    switch (byte_chr(sep, 4, s[i]))
+    {
+      case 0 :
+      case 1 :
+      case 2 : i++ ;
+      case 3 : break ;
+      case 4 :
+        strerr_dief2x(100, "invalid list argument: ", s) ;
+    }
+    if (!genalloc_append(diuint, list, &iv))
+      strerr_diefu1sys(111, "build interval list") ;
+  }
+}
+
+static int doit (int fd, diuint const *s, unsigned int len, unsigned int flags, char delim)
+{
+  char buf[BUFFER_INSIZE] ;
+  buffer b = BUFFER_INIT(&buffer_flush1read, fd, buf, BUFFER_INSIZE) ;
+  for (;;)
+  {
+    int r ;
+    satmp.len = 0 ;
+    r = skagetln(&b, &satmp, '\n') ;
+    if ((r == -1) && (errno != EPIPE)) return 0 ;
+    if (!r) break ;
+    if (flags & 2)
+    {
+      register unsigned int i = 0 ;
+      for (; i < len ; i++)
+      {
+        register unsigned int j = s[i].right ;
+        if (s[i].left >= satmp.len) break ;
+        if (!j || (j > satmp.len))
+        {
+          j = satmp.len ;
+          r = 0 ;
+        }
+        if (buffer_put(buffer_1, satmp.s + s[i].left - 1, j + 1 - s[i].left) == -1)
+          return 0 ;
+      }
+    }
+    else
+    {
+      register unsigned int i = 0, j = 0, count = 1 ;
+      for (; i < len ; i++)
+      {
+        for (; count < s[i].left ; count++)
+        {
+          j += byte_chr(satmp.s + j, satmp.len - j, delim) ;
+          if (j == satmp.len) break ;
+          j++ ;
+        }
+        if (j == satmp.len)
+        {
+          if (count == 1)
+          {
+            if ((flags & 1) && (buffer_put(buffer_1, satmp.s, satmp.len) < 0))
+              return 0 ;
+            r = 0 ;
+          }
+          break ;
+        }
+        for (; !s[i].right || (count <= s[i].right) ; count++)
+        {
+          register unsigned int k = byte_chr(satmp.s + j, satmp.len - j, delim) ;
+          if ((count > s[0].left) && (buffer_put(buffer_1, &delim, 1) < 0)) return 0 ;
+          if (buffer_put(buffer_1, satmp.s + j, k) < 0) return 0 ;
+          j += k ;
+          if (j == satmp.len)
+          {
+            r = 0 ;
+            break ;
+          }
+          j++ ;
+        }
+        if (j == satmp.len) break ;
+      }
+    }
+    if ((r > 0) && (buffer_put(buffer_1, "\n", 1) < 0)) return 0 ;
+  }
+  return 1 ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  genalloc list = GENALLOC_ZERO ; /* array of diuint */
+  char delim = '\t' ;
+  unsigned int what = 0 ;
+  PROG = "s6-cut" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    int flagnodel = 1 ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "nsb:c:f:d:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n': break ;  /* ignored */
+        case 's': flagnodel = 0 ; break ;
+        case 'd': delim = *l.arg ; break ;
+        case 'b':
+        case 'c':
+        {
+          if (what) strerr_dieusage(100, USAGE) ;
+          what = 2 ;
+          scanlist(&list, l.arg) ;
+          break ;
+        }
+        case 'f':
+        {
+          if (what) strerr_dieusage(100, USAGE) ;
+          what = 4 ;
+          scanlist(&list, l.arg) ;
+          break ;
+        }
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    what += flagnodel ;
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!genalloc_len(diuint, &list)) strerr_dieusage(100, USAGE) ;
+  diuintalloc_normalize(&list) ;
+
+  if (!argc)
+  {
+    if (!doit(0, genalloc_s(diuint, &list), genalloc_len(diuint, &list), what, delim))
+      strerr_diefu1sys(111, "cut stdin") ;
+  }
+  else
+  {
+    for (; *argv ; argv++)
+    {
+      if ((argv[0][0] == '-') && !argv[0][1])
+      {
+        if (!doit(0, genalloc_s(diuint, &list), genalloc_len(diuint, &list), what, delim))
+          strerr_diefu1sys(111, "process stdin") ;
+      }
+      else
+      {
+        int fd = open_readb(*argv) ;
+        if (fd == -1)
+          strerr_diefu3sys(111, "open ", *argv, " for reading") ;
+        if (!doit(fd, genalloc_s(diuint, &list), genalloc_len(diuint, &list), what, delim))
+          strerr_diefu2sys(111, "cut ", *argv) ;
+        fd_close(fd) ;
+      }
+    }
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-dirname.c b/src/skaembutils/s6-dirname.c
new file mode 100644
index 0000000..5883180
--- /dev/null
+++ b/src/skaembutils/s6-dirname.c
@@ -0,0 +1,40 @@
+/* ISC license. */
+
+#include <skalibs/sgetopt.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-dirname [ -n ] file"
+
+int main (int argc, char const *const *argv)
+{
+  stralloc sa = STRALLOC_ZERO ;
+  int nl = 1 ;
+  PROG = "s6-dirname" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "n", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n' : nl = 0 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  if (!sadirname(&sa, argv[0], str_len(argv[0])))
+    strerr_diefu2sys(111, "get dirname of ", argv[0]) ;
+  if (nl && !stralloc_catb(&sa, "\n", 1))
+    strerr_diefu2sys(111, "get dirname of ", argv[0]) ;
+  if (allwrite(1, sa.s, sa.len) < sa.len)
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-echo.c b/src/skaembutils/s6-echo.c
new file mode 100644
index 0000000..6d30576
--- /dev/null
+++ b/src/skaembutils/s6-echo.c
@@ -0,0 +1,38 @@
+/* ISC license. */
+
+#include <skalibs/sgetopt.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+
+#define USAGE "s6-echo [ -n ] [ -s sep ] args..."
+
+int main (int argc, char const *const *argv)
+{
+  char sep = ' ' ;
+  char donl = 1 ;
+  PROG = "s6-echo" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "ns:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n': donl = 0 ; break ;
+        case 's': sep = *l.arg ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  for ( ; *argv ; argv++)
+    if ((buffer_puts(buffer_1small, *argv) < 0)
+     || (argv[1] && (buffer_put(buffer_1small, &sep, 1) == -1)))
+      goto err ;
+  if (donl && (buffer_put(buffer_1small, "\n", 1) == -1)) goto err ;
+  if (!buffer_flush(buffer_1small)) goto err ;
+  return 0 ;
+err:
+  strerr_diefu1sys(111, "write to stdout") ;
+}
diff --git a/src/skaembutils/s6-env.c b/src/skaembutils/s6-env.c
new file mode 100644
index 0000000..b2e1312
--- /dev/null
+++ b/src/skaembutils/s6-env.c
@@ -0,0 +1,43 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/env.h>
+#include <skalibs/djbunix.h>
+#include <s6-portable-utils/config.h>
+
+#define USAGE "s6-env [ -i ] [ name=value... ] prog..."
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  stralloc modifs = STRALLOC_ZERO ;
+  char const *arg_zero[2] = { S6_PORTABLE_UTILS_BINPREFIX "s6-printenv", 0 } ;
+  char const *env_zero[1] = { 0 } ;
+  PROG = "s6-env" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "i", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'i': envp = env_zero ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  for (; argc ; argc--, argv++)
+  {
+    if (!(*argv)[str_chr(*argv, '=')]) break ;
+    if (!stralloc_cats(&modifs, *argv) || !stralloc_0(&modifs))
+      strerr_diefu1sys(111, "stralloc_cats") ;
+  }
+  if (!argc) argv = arg_zero ;
+  pathexec_r(argv, envp, env_len(envp), modifs.s, modifs.len) ;
+  stralloc_free(&modifs) ;
+  strerr_dieexec((errno == ENOENT) ? 127 : 126, argv[0]) ;
+}
diff --git a/src/skaembutils/s6-expr.c b/src/skaembutils/s6-expr.c
new file mode 100644
index 0000000..4404d44
--- /dev/null
+++ b/src/skaembutils/s6-expr.c
@@ -0,0 +1,211 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/fmtscan.h>
+#include <skalibs/strerr2.h>
+
+#define USAGE "s6-expr arithmetic expression"
+
+enum opnum
+{
+  T_DATA,
+  T_AND,
+  T_OR,
+  T_LEFTP,
+  T_RIGHTP,
+  T_EQUAL,
+  T_NEQUAL,
+  T_GREATER,
+  T_GREATERE,
+  T_LESSER,
+  T_LESSERE,
+  T_PLUS,
+  T_MINUS,
+  T_TIMES,
+  T_DIV,
+  T_MOD
+} ;
+
+struct token
+{
+  char const *string ;
+  enum opnum op ;
+  unsigned int type ;
+} ;
+
+struct node
+{
+  enum opnum op ;
+  unsigned int type ;
+  unsigned int arg1 ;
+  unsigned int arg2 ;
+  int data ;
+} ;
+
+static unsigned int lex (struct node *tree, char const *const *argv)
+{
+  static struct token const tokens[16] =
+  {
+    { "+", T_PLUS, 3 },
+    { "-", T_MINUS, 3 },
+    { "*", T_TIMES, 2 },
+    { "/", T_DIV, 2 },
+    { "%", T_MOD, 2 },
+    { "(", T_LEFTP, 7 },
+    { ")", T_RIGHTP, 8 },
+    { "=", T_EQUAL, 4 },
+    { "!=", T_NEQUAL, 4 },
+    { "<", T_LESSER, 4 },
+    { "<=", T_LESSERE, 4 },
+    { ">", T_GREATER, 4 },
+    { ">=", T_GREATERE, 4 },
+    { "|", T_OR, 6 },
+    { "&", T_AND, 5 },
+    { 0, 0, 0 }
+  } ;
+  register unsigned int pos = 0 ;
+
+  for (; argv[pos] ; pos++)
+  {
+    register unsigned int i = 0 ;
+    for (i = 0 ; tokens[i].string ; i++)
+      if (!str_diff(argv[pos], tokens[i].string))
+      {
+        tree[pos].op = tokens[i].op ;
+        tree[pos].type = tokens[i].type ;
+        break ;
+      }
+    if (!tokens[i].string)
+    {
+      tree[pos].op = T_DATA ;
+      tree[pos].type = 0 ;
+      if (!int_scan(argv[pos], &tree[pos].data))
+        strerr_dief1x(2, "invalid expression") ;
+    }
+  }
+  return pos ;
+}
+
+static void reduce (struct node *tree, register unsigned int *stack, register unsigned int *sp, unsigned int type)
+{
+  if (tree[stack[*sp-1]].type == type)
+  {
+    tree[stack[*sp-1]].arg1 = stack[*sp-2] ;
+    tree[stack[*sp-1]].arg2 = stack[*sp] ;
+    stack[*sp-2] = stack[*sp-1] ;
+    *sp -= 2 ;
+  }
+  tree[stack[*sp]].type = type + 7 ;
+}
+
+static unsigned int parse (struct node *tree, unsigned int n)
+{
+  static char const table[9][15] =
+  {
+    "xsssssssxzzzzzz",
+    "xxxxxxxx!zzzzzz",
+    "mxxxxxxxMszzzzz",
+    "mxxxxxxxMaszzzz",
+    "mxxxxxxxMacszzz",
+    "mxxxxxxxMacAszz",
+    "mxxxxxxxMacAOsz",
+    "xsssssssxzzzzzz",
+    "mxxxxxxxMacAOEs"
+  } ;
+  unsigned int stack[n] ;
+  unsigned int sp = 0, pos = 0 ;
+  char cont = 1 ;
+  stack[0] = n + 1 ;
+  tree[n].type = 8 ; /* add ) for the final reduce */
+  tree[n+1].type = 1 ; /* add EOF */
+  while (cont)
+  {
+    switch (table[tree[pos].type][tree[stack[sp]].type])
+    {
+      case 'x' :  _exit(2) ;
+      case '!' :  cont = 0 ; break ;
+      case 's' :  stack[++sp] = pos++ ; break ;
+      case 'm' :  reduce(tree, stack, &sp, 2) ; break ;
+      case 'a' :  reduce(tree, stack, &sp, 3) ; break ;
+      case 'c' :  reduce(tree, stack, &sp, 4) ; break ;
+      case 'A' :  reduce(tree, stack, &sp, 5) ; break ;
+      case 'O' :  reduce(tree, stack, &sp, 6) ; break ;
+      case 'E' :  tree[stack[sp]].type = 14 ; break ;
+      case 'M' : 
+      {
+        if (tree[stack[sp-2]].type != 7) _exit(2) ;
+        stack[sp-2] = stack[sp-1] ;
+        sp -= 2 ;
+        reduce(tree, stack, &sp, 2) ;
+        break ;
+      }
+      case 'z' : 
+      default : strerr_dief1x(101, "internal error in parse, please submit a bug-report.") ; /* can't happen */
+    }
+  }
+  if (sp != 2) strerr_dief1x(2, "invalid expression") ;
+  return stack[1] ;
+}
+
+static int run (struct node const *tree, unsigned int root)
+{
+  switch (tree[root].op)
+  {
+    case T_DATA :
+      return tree[root].data ;
+    case T_OR :
+    {
+      int r = run(tree, tree[root].arg1) ;
+      return r ? r : run(tree, tree[root].arg2) ;
+    }
+    case T_AND :
+    {
+      int r = run(tree, tree[root].arg1) ;
+      return r ? run(tree, tree[root].arg2) ? r : 0 : 0 ;
+    }
+    case T_EQUAL :
+      return run(tree, tree[root].arg1) == run(tree, tree[root].arg2) ;
+    case T_NEQUAL :
+      return run(tree, tree[root].arg1) != run(tree, tree[root].arg2) ;
+    case T_GREATER :
+      return run(tree, tree[root].arg1) > run(tree, tree[root].arg2) ;
+    case T_GREATERE :
+      return run(tree, tree[root].arg1) >= run(tree, tree[root].arg2) ;
+    case T_LESSER :
+      return run(tree, tree[root].arg1) < run(tree, tree[root].arg2) ;
+    case T_LESSERE :
+      return run(tree, tree[root].arg1) <= run(tree, tree[root].arg2) ;
+    case T_PLUS :
+      return run(tree, tree[root].arg1) + run(tree, tree[root].arg2) ;
+    case T_MINUS :
+      return run(tree, tree[root].arg1) - run(tree, tree[root].arg2) ;
+    case T_TIMES :
+      return run(tree, tree[root].arg1) * run(tree, tree[root].arg2) ;
+    case T_DIV :
+      return run(tree, tree[root].arg1) / run(tree, tree[root].arg2) ;
+    case T_MOD :
+      return run(tree, tree[root].arg1) % run(tree, tree[root].arg2) ;
+    default: strerr_dief1x(101, "internal error in run, please submit a bug-report") ;
+  }
+}
+
+int main (int argc, char const *const *argv)
+{
+  char fmt[UINT_FMT+1] ;
+  int val ;
+  unsigned int len ;
+  PROG = "s6-expr" ;
+  if (argc <= 1) return 2 ;
+  {
+    struct node tree[argc + 1] ;
+    val = run(tree, parse(tree, lex(tree, argv+1))) ;
+  }
+  len = int_fmt(fmt, val) ;
+  fmt[len++] = '\n' ;
+  if (allwrite(1, fmt, len) < len)
+    strerr_diefu1sys(111, "write to stdout") ;
+  return !val ;
+}
diff --git a/src/skaembutils/s6-false.c b/src/skaembutils/s6-false.c
new file mode 100644
index 0000000..fb13dcd
--- /dev/null
+++ b/src/skaembutils/s6-false.c
@@ -0,0 +1,6 @@
+/* ISC license. */
+
+int main ()
+{
+  return 1 ;
+}
diff --git a/src/skaembutils/s6-format-filter.c b/src/skaembutils/s6-format-filter.c
new file mode 100644
index 0000000..78e4437
--- /dev/null
+++ b/src/skaembutils/s6-format-filter.c
@@ -0,0 +1,61 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/buffer.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-format-filter format [ args... ]"
+
+int main (int argc, char const *const *argv)
+{
+  stralloc src = STRALLOC_ZERO ;
+  stralloc dst = STRALLOC_ZERO ;
+  char vars[12] = "s0123456789" ;
+  char const *args[12] = { "" } ;
+  char const *format ;
+  PROG = "s6-format-filter" ;
+  argc-- ; args[1] = *argv++ ;
+  if (!argc--) strerr_dieusage(100, USAGE) ;
+  format = *argv++ ;
+  if (argc > 9) argc = 9 ;
+  vars[argc+2] = 0 ;
+  {
+    register unsigned int i = 0 ;
+    for (; i < (unsigned int)argc ; i++) args[2+i] = argv[i] ;
+  }
+  if (!string_format(&dst, vars, format, args))
+    strerr_diefu1sys(111, "compile format") ;
+
+  for (;;)
+  {
+    register int r ;
+    src.len = 0 ;
+    dst.len = 0 ;
+    r = skagetln(buffer_0f1, &src, '\n') ;
+    if (!r) break ;
+    else if (r < 0)
+    {
+      if ((errno != EPIPE) || !stralloc_0(&src))
+        strerr_diefu1sys(111, "read from stdin") ;
+    }
+    else src.s[src.len-1] = 0 ;
+    args[0] = src.s ;    
+    if (!string_format(&dst, vars, format, args))
+    {
+      int e = errno ;
+      buffer_flush(buffer_1) ;
+      errno = e ;
+      strerr_diefu1sys(111, "format") ;
+    }
+    if (r > 0)
+    {
+      if (!stralloc_catb(&dst, "\n", 1))
+        strerr_diefu1sys(111, "format") ;
+    }
+    if (buffer_put(buffer_1, dst.s, dst.len) < 0)
+      strerr_diefu1sys(111, "write to stdout") ;
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-grep.c b/src/skaembutils/s6-grep.c
new file mode 100644
index 0000000..cd991e7
--- /dev/null
+++ b/src/skaembutils/s6-grep.c
@@ -0,0 +1,136 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <regex.h>
+#include <string.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/buffer.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-grep [ -E | -F ] [ -i ] [ -c ] [ -n ] [ -q ] [ -v ] pattern"
+
+typedef struct flags_s flags_t, *flags_t_ref ;
+struct flags_s
+{
+  unsigned int extended : 1 ;
+  unsigned int ignorecase: 1 ;
+  unsigned int fixed : 1 ;
+  unsigned int count : 1 ;
+  unsigned int num : 1 ;
+  unsigned int quiet : 1 ;
+  unsigned int not : 1 ;
+} ;
+#define FLAGS_ZERO { .extended = 0, .ignorecase = 0, .fixed = 0, .count = 0, .num = 0, .quiet = 0, .not = 0 }
+
+int main (int argc, char const *const *argv)
+{
+  unsigned int count = 0 ;
+  flags_t flags = FLAGS_ZERO ;
+  PROG = "s6-grep" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "EFicnqv", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'E': flags.extended = 1 ; break ;
+        case 'F': flags.fixed = 1 ; break ;
+        case 'i': flags.ignorecase = 1 ; break ;
+        case 'c': flags.count = 1 ; break ;
+        case 'n': flags.num = 1 ; break ;
+        case 'q': flags.quiet = 1 ; break ;
+        case 'v': flags.not = 1 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  {
+    stralloc line = STRALLOC_ZERO ;
+    regex_t re ;
+    unsigned int num = 0 ;
+    unsigned int arglen ;
+    if (flags.fixed)
+    {
+      if (flags.ignorecase) arglen = str_len(argv[0]) ;
+    }
+    else
+    {
+      register int e = regcomp(&re, argv[0], REG_NOSUB | (flags.extended ? REG_EXTENDED : 0) | (flags.ignorecase ? REG_ICASE : 0)) ;
+      if (e)
+      {
+        char buf[256] ;
+        regerror(e, &re, buf, 256) ;
+        strerr_diefu2x(111, "compile regular expression: ", buf) ;
+      }
+    }
+
+    for (;;)
+    {
+      register int r ;
+      line.len = 0 ;
+      r = skagetln(buffer_0f1, &line, '\n') ;
+      if (!r) break ;
+      if (r < 0)
+      {
+        if ((errno != EPIPE) || !stralloc_catb(&line, "\n", 1))
+          strerr_diefu1sys(111, "read from stdin") ;
+      }
+      num++ ; line.s[line.len-1] = 0 ;
+      if (flags.fixed)
+      {
+        if (flags.ignorecase)
+          r = case_str(line.s, argv[0]) >= arglen ;
+        else
+          r = !strstr(line.s, argv[0]) ;
+      }
+      else
+      {
+        r = regexec(&re, line.s, 0, 0, 0) ;
+        if (r && r != REG_NOMATCH)
+        {
+          char buf[256] ;
+          regerror(r, &re, buf, 256) ;
+          strerr_diefu2x(111, "match regular expression: ", buf) ;
+        }
+      }
+      line.s[line.len-1] = '\n' ;
+      if (!r ^ flags.not)
+      {
+        count++ ;
+        if (!flags.quiet && !flags.count)
+        {
+          if (flags.num)
+          {
+            char fmt[UINT_FMT] ;
+            register unsigned int n = uint_fmt(fmt, num) ;
+            fmt[n++] = ':' ;
+            if (buffer_put(buffer_1, fmt, n) < (int)n)
+              strerr_diefu1sys(111, "write to stdout") ;
+          }
+          if (buffer_put(buffer_1, line.s, line.len) < (int)line.len)
+            strerr_diefu1sys(111, "write to stdout") ;
+        }
+      }
+    }
+    if (flags.quiet) return !count ;
+    stralloc_free(&line) ;
+    if (!flags.fixed) regfree(&re) ;
+  }
+  if (flags.count)
+  {
+    char fmt[UINT_FMT] ;
+    register unsigned int n = uint_fmt(fmt, count) ;
+    fmt[n++] = '\n' ;
+    if (buffer_put(buffer_1, fmt, n) < (int)n)
+      strerr_diefu1sys(111, "write to stdout") ;
+  }
+  return !count ;
+}
diff --git a/src/skaembutils/s6-head.c b/src/skaembutils/s6-head.c
new file mode 100644
index 0000000..1ef24c0
--- /dev/null
+++ b/src/skaembutils/s6-head.c
@@ -0,0 +1,159 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/buffer.h>
+#include <skalibs/siovec.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-head [ -S ] [ -1..9 | -n lines | -c chars ] [ file... ]"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+typedef int headfunc_t (int, unsigned int) ;
+typedef headfunc_t *headfunc_t_ref ;
+
+static int dolines (int fd, unsigned int lines)
+{
+  char buf[BUFFER_INSIZE] ;
+  buffer in = BUFFER_INIT(&buffer_read, fd, buf, BUFFER_INSIZE) ;
+  buffer out = BUFFER_INIT(&buffer_write, 1, buf, BUFFER_INSIZE) ;
+  siovec_t v[2] ;
+  while (lines)
+  {
+    unsigned int w = 0 ;
+    register int r = buffer_fill(&in) ;
+    if (r <= 0) return !r ;
+    out.c.n = in.c.n ; out.c.p = in.c.p ;
+    buffer_rpeek(&in, v) ;
+    for (;;)
+    {
+      unsigned int n = siovec_len(v, 2) ;
+      register unsigned int i ;
+      if (!n) break ;
+      i = siovec_bytechr(v, 2, '\n') ;
+      if (i < n)
+      {
+        w += i+1 ;
+        siovec_seek(v, 2, i+1) ;
+        if (!--lines)
+        {
+          out.c.n = (out.c.p + w) % out.c.a ;
+          break ;
+        }
+      }
+      else siovec_seek(v, 2, i) ;
+    }
+    if (!buffer_flush(&out)) return 0 ;
+    in.c.n = out.c.n ; in.c.p = out.c.p ;
+  }
+  return 1 ;
+}
+
+static int safedolines (int fd, unsigned int lines)
+{
+  char tmp[lines] ;
+  while (lines)
+  {
+    unsigned int r = allread(fd, tmp, lines) ;
+    if ((r < lines) && (errno != EPIPE)) return 0 ;
+    lines -= byte_count(tmp, r, '\n') ;
+    if (buffer_put(buffer_1, tmp, r) < (int)r) return 0 ;
+  }
+  if (!buffer_flush(buffer_1)) return 0 ;
+  return 1 ;
+}
+
+static int safedochars (int fd, unsigned int chars)
+{
+  return (fd_catn(fd, 1, chars) >= chars) ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  headfunc_t_ref f ;
+  unsigned int lines = 10 ;
+  int islines = 1, safe = 0 ;
+  PROG = "s6-head" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    int done = 0 ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "S123456789n:c:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'S' : safe = 1 ; break ;
+        case '1' :
+        case '2' :
+        case '3' :
+        case '4' :
+        case '5' :
+        case '6' :
+        case '7' :
+        case '8' :
+        case '9' :
+        {
+          if (done) dieusage() ;
+          islines = 1 ;
+          lines = opt - '0' ;
+          done = 1 ;
+          break ;
+        }
+        case 'n' :
+        {
+          if (done || !uint0_scan(l.arg, &lines))
+            strerr_dieusage(100, USAGE) ;
+          islines = 1 ;
+          done = 1 ;
+          break ;
+        }
+        case 'c' :
+        {
+          if (done || !uint0_scan(l.arg, &lines))
+            strerr_dieusage(100, USAGE) ;
+          islines = 0 ;
+          done = 1 ;
+          break ;
+        }
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (argc) safe = 0 ;
+  f = islines ? safe ? &safedolines : &dolines : &safedochars ;
+  if (!argc)
+  {
+    if (!(*f)(0, lines))
+      strerr_diefu1sys(111, "head stdin") ;
+  }
+  else
+  {
+    unsigned int i = 0 ;
+    for (; argv[i] ; i++)
+    {
+      int fd ;
+      if (argc >= 2)
+      {
+        if (i) buffer_putnoflush(buffer_1, "\n", 1) ;
+        buffer_putnoflush(buffer_1, "==> ", 4) ;
+        if ((buffer_puts(buffer_1, argv[i]) <= 0)
+         || (buffer_putflush(buffer_1, " <==\n", 5) < 0))
+          strerr_diefu1sys(111, "write to stdout") ;
+      }
+      if ((argv[i][0] == '-') && !argv[i][1]) fd = 0 ;
+      else fd = open_readb(argv[i]) ;
+      if (fd == -1)
+        strerr_diefu3sys(111, "open ", argv[i], " for reading") ;
+      if (!(*f)(fd, lines))
+        strerr_diefu2sys(111, "head ", argv[i]) ;
+      fd_close(fd) ;
+    }
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-linkname.c b/src/skaembutils/s6-linkname.c
new file mode 100644
index 0000000..a9425a1
--- /dev/null
+++ b/src/skaembutils/s6-linkname.c
@@ -0,0 +1,45 @@
+/* ISC license. */
+
+#include <skalibs/bytestr.h>
+#include <skalibs/buffer.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-linkname [ -n ] [ -f ] link"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+int main (int argc, char const *const *argv)
+{
+  stralloc sa = STRALLOC_ZERO ;
+  int path = 0, nl = 1 ;
+  PROG = "s6-linkname" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "nf", &l) ;
+      if (opt == -1) break ;
+      switch(opt)
+      {
+        case 'n' : nl = 0 ; break ;
+        case 'f' : path = 1 ; break ;
+        default :  dieusage() ;
+      }
+    }
+    argv += l.ind ; argc -= l.ind ;
+  }
+  if (!argc) dieusage() ;
+
+  if ((path ? sarealpath(&sa, *argv) : sareadlink(&sa, *argv)) < 0)
+    strerr_diefu2sys(111, "resolve ", *argv) ;
+
+  if ((buffer_put(buffer_1small, sa.s, sa.len) < 0)
+   || (nl && (buffer_put(buffer_1small, "\n", 1)) < 0)
+   || (!buffer_flush(buffer_1small)))
+    strerr_diefu1sys(111, "write to stdout") ;
+
+ /* stralloc_free(&sa) ; */
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-ln.c b/src/skaembutils/s6-ln.c
new file mode 100644
index 0000000..7f6f7b6
--- /dev/null
+++ b/src/skaembutils/s6-ln.c
@@ -0,0 +1,145 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#ifdef SKALIBS_HASLINKAT
+#include <skalibs/nonposix.h>
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/random.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-ln [ -s ] [ -f ] [ -L ] [ -P ] src... dest"
+
+typedef int linkfunc_t (char const *, char const *) ;
+typedef linkfunc_t *linkfunc_t_ref ;
+
+typedef void ln_t (char const *, char const *, linkfunc_t_ref) ;
+typedef ln_t *ln_t_ref ;
+
+#ifdef SKALIBS_HASLINKAT
+
+static int linknoderef (char const *old, char const *new)
+{
+  return linkat(AT_FDCWD, old, AT_FDCWD, new, 0) ;
+}
+
+static int linkderef (char const *old, char const *new)
+{
+  return linkat(AT_FDCWD, old, AT_FDCWD, new, AT_SYMLINK_FOLLOW) ;
+}
+
+#else /* can't implement SUSv4, default to link */
+
+# define linknoderef link
+# define linkderef link
+
+#endif
+
+static void force (char const *old, char const *new, linkfunc_t_ref doit)
+{
+  if ((*doit)(old, new) == -1)
+  {
+    unsigned int base = satmp.len ;
+    if (errno != EEXIST)
+      strerr_diefu5sys(111, "make a link", " from ", new, " to ", old) ;
+    if (!stralloc_catb(&satmp, new, str_len(new))
+     || (random_sauniquename(&satmp, 8) == -1)
+     || !stralloc_0(&satmp))
+      strerr_diefu2sys(111, "make a unique name for ", old) ;
+    if ((*doit)(old, satmp.s + base) == -1)
+      strerr_diefu3sys(111, "make a link", " to ", old) ;
+    if (rename(satmp.s + base, new) == -1)
+    {
+      unlink(satmp.s + base) ;
+      strerr_diefu2sys(111, "atomically replace ", new) ;
+    }
+    satmp.len = base ;
+  }
+}
+
+static void noforce (char const *old, char const *new, linkfunc_t_ref doit)
+{
+  if ((*doit)(old, new) == -1)
+    strerr_diefu5sys(111, "make a link", " from ", new, " to ", old) ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  linkfunc_t_ref mylink = &link ; /* default to system behaviour */
+  ln_t_ref f = &noforce ;
+  PROG = "s6-ln" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "sfLP", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 's': mylink = &symlink ; break ;
+        case 'f': f = &force ; break ;
+        case 'L': if (mylink != &symlink) mylink = &linkderef ; break ;
+        case 'P': if (mylink != &symlink) mylink = &linknoderef ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (argc < 2) strerr_dieusage(100, USAGE) ;
+  if (argc > 2)
+  {
+    stralloc sa = STRALLOC_ZERO ;
+    unsigned int i = 0 ;
+    unsigned int base ;
+    if (!stralloc_cats(&sa, argv[argc-1]) || !stralloc_catb(&sa, "/", 1))
+      strerr_diefu1sys(111, "stralloc_cats") ;
+    base = sa.len ;
+    for (; i < (unsigned int)(argc-1) ; i++)
+    {
+      sa.len = base ;
+      if (!sabasename(&sa, argv[i], str_len(argv[i])))
+        strerr_diefu1sys(111, "sabasename") ;
+      if (!stralloc_0(&sa)) strerr_diefu1sys(111, "stralloc_0") ;
+      (*f)(argv[i], sa.s, mylink) ;
+    }
+    return 0 ;
+  }
+
+  {
+    struct stat st ;
+    if (stat(argv[1], &st) < 0)
+    {
+      if (errno != ENOENT) strerr_diefu2sys(111, "stat ", argv[1]) ;
+      (*f)(argv[0], argv[1], mylink) ;
+      return 0 ;
+    }
+    if (!S_ISDIR(st.st_mode))
+    {
+      (*f)(argv[0], argv[1], mylink) ;
+      return 0 ;
+    }
+  }
+
+  {
+    stralloc sa = STRALLOC_ZERO ;
+    if (!stralloc_cats(&sa, argv[1])
+      || !stralloc_catb(&sa, "/", 1)
+      || !sabasename(&sa, argv[0], str_len(argv[0]))
+      || !stralloc_0(&sa))
+        strerr_diefu1sys(111, "stralloc_catb") ;
+      (*f)(argv[0], sa.s, mylink) ;
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-ls.c b/src/skaembutils/s6-ls.c
new file mode 100644
index 0000000..25045a7
--- /dev/null
+++ b/src/skaembutils/s6-ls.c
@@ -0,0 +1,56 @@
+/* ISC license. */
+
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/direntry.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+
+#define USAGE "s6-ls [ -0 ] [ -a | -A ] [ -x exclude ] dir"
+
+int main (int argc, char const *const *argv)
+{
+  unsigned int all = 0 ;
+  char const *exclude = 0 ;
+  char delim = '\n' ;
+  PROG = "s6-ls" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "0aAx:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case '0': delim = '\0' ; break ;
+        case 'a': all = 1 ; break ;
+        case 'A': all = 2 ; break ;
+        case 'x': exclude = l.arg ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  {
+    direntry *d ;
+    DIR *dir = opendir(*argv) ;
+    if (!dir)
+      strerr_diefu2sys(111, "open directory ", *argv) ;
+    while ((d = readdir(dir)))
+    {
+      if ((d->d_name[0] == '.') && (all < 2))
+      {
+        if (!all || !d->d_name[1] || ((d->d_name[1] == '.') && !d->d_name[2])) continue ;
+      }
+      if (exclude && !str_diff(exclude, d->d_name)) continue ;
+      if ((buffer_puts(buffer_1, d->d_name) < 0)
+       || (buffer_put(buffer_1, &delim, 1) < 0))
+        strerr_diefu1sys(111, "write to stdout") ;
+    }
+    dir_close(dir) ;
+  }
+  if (!buffer_flush(buffer_1))
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-maximumtime.c b/src/skaembutils/s6-maximumtime.c
new file mode 100644
index 0000000..571914f
--- /dev/null
+++ b/src/skaembutils/s6-maximumtime.c
@@ -0,0 +1,99 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <errno.h>
+#include <unistd.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/uint.h>
+#include <skalibs/error.h>
+#include <skalibs/sig.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-maximumtime [ -0 | -a | -b | -i | -k | -q | -t | -x | -1 | -2 ] milliseconds prog..."
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  unsigned int timeout ;
+  tain_t stamp, deadline ;
+  iopause_fd x[1] = { { .fd = -1, .events = IOPAUSE_READ, .revents = 0 } } ;
+  pid_t pid = 0 ;
+  int tosend = SIGTERM ;
+  PROG = "s6-maximumtime" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "0abikqtx12", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case '0': tosend = 0 ; break ;
+        case 'a': tosend = SIGALRM ; break ;
+        case 'b': tosend = SIGABRT ; break ;
+        case 'i': tosend = SIGINT ; break ;
+        case 'k': tosend = SIGKILL ; break ;
+        case 'q': tosend = SIGQUIT ; break ;
+        case 't': tosend = SIGTERM ; break ;
+        case 'x': tosend = SIGXCPU ; break ;
+        case '1': tosend = SIGUSR1 ; break ;
+        case '2': tosend = SIGUSR2 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  if ((argc < 2) || !uint0_scan(argv[0], &timeout)) strerr_dieusage(100, USAGE) ;
+  if (!timeout) timeout = 1 ;
+  if (!tain_from_millisecs(&deadline, timeout))
+    strerr_diefu1sys(111, "taia_from_millisecs") ;
+
+  x[0].fd = selfpipe_init() ;
+  if (x[0].fd < 0) strerr_diefu1sys(111, "selfpipe_init") ;
+  
+  if (selfpipe_trap(SIGCHLD) < 0) strerr_diefu1sys(111, "selfpipe_trap") ;
+
+  pid = child_spawn0(argv[1], argv+1, envp) ;
+  if (!pid)  strerr_diefu2sys(111, "spawn ", argv[1]) ;
+  tain_now(&stamp) ;
+  tain_add(&deadline, &deadline, &stamp) ;
+
+  for (;;)
+  {
+    int r = iopause_stamp(x, 1, &deadline, &stamp) ;
+    if (r < 0) strerr_diefu1sys(111, "iopause") ;
+    if (!r) break ;
+    if (x[0].revents & IOPAUSE_READ)
+    {
+      int cont = 1 ;
+      while (cont)
+      {
+        switch (selfpipe_read())
+        {
+          case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
+          case 0 : cont = 0 ; break ;
+          case SIGCHLD :
+          {
+            int wstat ;
+            if (wait_pid_nohang(pid, &wstat) == pid)
+            {
+              if (WIFSIGNALED(wstat))
+                strerr_diew1x(111, "child process crashed") ;
+              else return WEXITSTATUS(wstat) ;
+            }
+          }
+          default : strerr_diefu1x(101, "internal error, please submit a bug-report.") ;
+        }
+      }
+    }
+  }
+  kill(pid, tosend) ;
+  errno = ETIMEDOUT ;
+  strerr_diewu1sys(99, "wait for child process") ;
+}
diff --git a/src/skaembutils/s6-mkdir.c b/src/skaembutils/s6-mkdir.c
new file mode 100644
index 0000000..92bae67
--- /dev/null
+++ b/src/skaembutils/s6-mkdir.c
@@ -0,0 +1,79 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+
+#define USAGE "s6-mkdir [ -p ] [ -v ] [ -m mode ] dir"
+
+static int doit (char const *s, unsigned int mode, int verbose, int ee)
+{
+  if (mkdir(s, mode) == -1)
+  {
+    if (ee || (errno != EEXIST))
+    {
+      strerr_warnwu2sys("mkdir ", s) ;
+      return 111 ;
+    }
+  }
+  else if (verbose)
+  {
+    buffer_puts(buffer_2, PROG) ;
+    buffer_puts(buffer_2, ": created directory ") ;
+    buffer_puts(buffer_2, s) ;
+    buffer_putflush(buffer_2, "\n", 1) ;
+  }
+  return 0 ;
+}
+
+static int doparents (char const *s, unsigned int mode, int verbose)
+{
+  unsigned int n = str_len(s), i = 0 ;
+  char tmp[n+1] ;
+  for (; i < n ; i++)
+  {
+    if ((s[i] == '/') && i)
+    {
+      register int e ;
+      tmp[i] = 0 ;
+      e = doit(tmp, mode, verbose, 0) ;
+      if (e) return e ;
+    }
+    tmp[i] = s[i] ;
+  }
+  return doit(s, mode, verbose, 0) ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  int parents = 0, verbose = 0 ;
+  unsigned int mode = 0777 ;
+  int e = 0 ;
+  PROG = "s6-mkdir" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "pvm:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'p': parents = 1 ; break ;
+        case 'v': verbose = 1 ; break ;
+        case 'm': if (uint_oscan(l.arg, &mode)) break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  for ( ; *argv ; argv++)
+    e |= parents ? doparents(*argv, mode, verbose) :
+                   doit(*argv, mode, verbose, 1) ;
+  return e ;
+}
diff --git a/src/skaembutils/s6-mkfifo.c b/src/skaembutils/s6-mkfifo.c
new file mode 100644
index 0000000..9278eb9
--- /dev/null
+++ b/src/skaembutils/s6-mkfifo.c
@@ -0,0 +1,36 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-mkfifo [ -m mode ] fifo..."
+
+int main (int argc, char const *const *argv)
+{
+  unsigned int mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH ;
+  PROG = "s6-mkfifo" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "m:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'm': if (uint0_oscan(l.arg, &mode)) break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  umask(S_IXUSR|S_IXGRP|S_IXOTH) ;
+  for (; *argv ; argv++)
+    if (mkfifo(*argv, mode) < 0)
+      strerr_diefu2sys(111, "mkfifo ", *argv) ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-nice.c b/src/skaembutils/s6-nice.c
new file mode 100644
index 0000000..ec9f477
--- /dev/null
+++ b/src/skaembutils/s6-nice.c
@@ -0,0 +1,46 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/uint.h>
+#include <skalibs/fmtscan.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-nice [ -I | -i ] [ -n value ] prog..."
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  int incr = 10 ;
+  int strict = 0 ;
+  PROG = "s6-nice" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "Iin:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'I' : strict = 0 ; break ;
+        case 'i' : strict = 1 ; break ;
+        case 'n': if (!int_scan(l.arg, &incr)) strerr_dieusage(100, USAGE) ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+
+  errno = 0 ;
+  if ((nice(incr) < 0) && errno)
+  {
+    char fmt[1+UINT_FMT] ;
+    fmt[int_fmt(fmt, incr)] = 0 ;
+    if (strict) strerr_diefu2sys(111, "nice to ", fmt) ;
+    else strerr_warnwu2sys("nice to ", fmt) ;
+  }
+  pathexec_run(argv[0], argv, envp) ;
+  strerr_dieexec((errno == ENOENT) ? 127 : 126, argv[0]) ;
+}
diff --git a/src/skaembutils/s6-nuke.c b/src/skaembutils/s6-nuke.c
new file mode 100644
index 0000000..cda1279
--- /dev/null
+++ b/src/skaembutils/s6-nuke.c
@@ -0,0 +1,50 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <signal.h>
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/sig.h>
+
+#define USAGE "s6-nuke [ -h | -t | -k ]"
+
+int main (int argc, char const *const *argv)
+{
+  int doterm = 0, dohangup = 0, dokill = 0 ;
+  PROG = "s6-nuke" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "htk", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'h': dohangup = 1 ; break ;
+        case 't': doterm = 1 ; break ;
+        case 'k': dokill = 1 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  if (dohangup)
+  {
+    sig_ignore(SIGHUP) ;
+    kill(-1, SIGHUP) ;
+  }
+
+  if (doterm)
+  {
+    sig_ignore(SIGTERM) ;
+    kill(-1, SIGTERM) ;
+    kill(-1, SIGCONT) ;
+  }
+
+  if (dokill) kill(-1, SIGKILL) ;
+
+  if (errno) strerr_diefu1sys(111, "kill") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-pause.c b/src/skaembutils/s6-pause.c
new file mode 100644
index 0000000..8eafdce
--- /dev/null
+++ b/src/skaembutils/s6-pause.c
@@ -0,0 +1,9 @@
+/* ISC license. */
+
+#include <unistd.h>
+
+int main ()
+{
+  pause() ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-printenv.c b/src/skaembutils/s6-printenv.c
new file mode 100644
index 0000000..3f4571b
--- /dev/null
+++ b/src/skaembutils/s6-printenv.c
@@ -0,0 +1,51 @@
+/* ISC license. */
+
+#include <skalibs/bytestr.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/netstring.h>
+
+#define USAGE "s6-printenv [ -n ] [ -0 | -d delimchar ]"
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  char delim = '\n' ;
+  int zero = 0, nl = 1 ;
+  PROG = "s6-printenv" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "nd:0", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n' : nl = 0 ; break ;
+        case 'd' : delim = *l.arg ; break ;
+        case '0' : zero = 1 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (zero) delim = 0 ;
+  for (; *envp ; envp++)
+  {
+    if (delim || zero)
+    {
+      if ((buffer_puts(buffer_1, *envp) < 0)
+       || ((nl || envp[1]) && (buffer_put(buffer_1, &delim, 1) < 0)))
+        strerr_diefu1sys(111, "write to stdout") ;
+    }
+    else
+    {
+      unsigned int written = 0 ;
+      if (!netstring_put(buffer_1, *envp, str_len(*envp), &written))
+        strerr_diefu1sys(111, "write a netstring to stdout") ;
+    }
+  }
+  if (!buffer_flush(buffer_1))
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-quote-filter.c b/src/skaembutils/s6-quote-filter.c
new file mode 100644
index 0000000..d9489a1
--- /dev/null
+++ b/src/skaembutils/s6-quote-filter.c
@@ -0,0 +1,72 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/buffer.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-quote-filter [ -u ] [ -d delim ]"
+
+int main (int argc, char const *const *argv)
+{
+  stralloc src = STRALLOC_ZERO ;
+  stralloc dst = STRALLOC_ZERO ;
+  char const *delim = "\"" ;
+  unsigned int delimlen ;
+  unsigned int startquote = 1 ;
+  PROG = "s6-quote-filter" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "ud:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'u' : startquote = 0 ; break ;
+        case 'd': delim = l.arg ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  delimlen = str_len(delim) ;
+  if (startquote)
+  {
+    if(!delimlen) strerr_dief1x(100, "no character to quote with!") ;
+    if (!stralloc_catb(&dst, delim, 1))
+      strerr_diefu1sys(111, "stralloc_catb") ;
+  }
+  for (;;)
+  {
+    int r ;
+    src.len = 0 ;
+    r = skagetln(buffer_0f1, &src, '\n') ;
+    if (!r) break ;
+    if ((r < 0) && (errno != EPIPE))
+      strerr_diefu1sys(111, "read from stdin") ;
+    dst.len = startquote ;
+    if (!string_quote_nodelim_mustquote(&dst, src.s, src.len - (r > 0), delim, delimlen))
+    {
+      int e = errno ;
+      buffer_flush(buffer_1) ;
+      errno = e ;
+      strerr_diefu1sys(111, "quote") ;
+    }
+    if (startquote)
+    {
+      if (!stralloc_catb(&dst, delim, 1))
+        strerr_diefu1sys(111, "stralloc_catb") ;
+    }
+    if (r > 0)
+    {
+      if (!stralloc_catb(&dst, "\n", 1))
+        strerr_diefu1sys(111, "stralloc_catb") ;
+    }
+    if (buffer_put(buffer_1, dst.s, dst.len) < 0)
+      strerr_diefu1sys(111, "write to stdout") ;
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-quote.c b/src/skaembutils/s6-quote.c
new file mode 100644
index 0000000..b370e39
--- /dev/null
+++ b/src/skaembutils/s6-quote.c
@@ -0,0 +1,58 @@
+/* ISC license. */
+
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-quote [ -n ] [ -u ] [ -d delim ] string"
+
+int main (int argc, char const *const *argv)
+{
+  stralloc sa = STRALLOC_ZERO ;
+  char const *delim = "\"" ;
+  unsigned int delimlen ;
+  int nl = 1 ;
+  int startquote = 1 ;
+  PROG = "s6-quote" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "nud:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n' : nl = 0 ; break ;
+        case 'u' : startquote = 0 ; break ;
+        case 'd': delim = l.arg ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  delimlen = str_len(delim) ;
+  if (startquote)
+  {
+    if (!delimlen) strerr_dief1x(100, "no character to quote with!") ;
+    if (!stralloc_catb(&sa, delim, 1))
+      strerr_diefu1sys(111, "stralloc_catb") ;
+  }
+  if (!string_quote_nodelim_mustquote(&sa, *argv, str_len(*argv), delim, delimlen))
+    strerr_diefu1sys(111, "quote") ;
+  if (startquote)
+  {
+    if (!stralloc_catb(&sa, delim, 1))
+      strerr_diefu1sys(111, "stralloc_catb") ;
+  }
+  if (nl)
+  {
+    if (!stralloc_catb(&sa, "\n", 1))
+      strerr_diefu1sys(111, "stralloc_catb") ;
+  }
+  if (allwrite(1, sa.s, sa.len) < sa.len)
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-rename.c b/src/skaembutils/s6-rename.c
new file mode 100644
index 0000000..55c92fa
--- /dev/null
+++ b/src/skaembutils/s6-rename.c
@@ -0,0 +1,16 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <skalibs/strerr2.h>
+
+#define USAGE "s6-rename old new"
+
+int main (int argc, char const *const *argv)
+{
+  PROG = "s6-rename" ;
+  if (argc < 3) strerr_dieusage(100, USAGE) ;
+  if (rename(argv[1], argv[2]) == -1)
+    strerr_diefu4sys(111, "rename ", argv[1], " to ", argv[2]) ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-rmrf.c b/src/skaembutils/s6-rmrf.c
new file mode 100644
index 0000000..4d57530
--- /dev/null
+++ b/src/skaembutils/s6-rmrf.c
@@ -0,0 +1,17 @@
+/* ISC license. */
+
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-rmrf file ..."
+
+int main (int argc, char const *const *argv)
+{
+  char const *const *p = argv + 1 ;
+  PROG = "s6-rmrf" ;
+  if (argc < 2) strerr_dieusage(100, USAGE) ;
+  for (; *p ; p++)
+    if (rm_rf(*p) == -1)
+      strerr_diefu2sys(111, "remove ", argv[1]) ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-sleep.c b/src/skaembutils/s6-sleep.c
new file mode 100644
index 0000000..ea25514
--- /dev/null
+++ b/src/skaembutils/s6-sleep.c
@@ -0,0 +1,46 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/uint.h>
+#include <skalibs/tai.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/iopause.h>
+
+#define USAGE "s6-sleep [ -m ] duration prog..."
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  unsigned int n ;
+  int milli = 0 ;
+  PROG = "s6-sleep" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "m", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'm': milli = 1 ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  if (!uint0_scan(argv[0], &n)) strerr_dieusage(100, USAGE) ;
+
+  {
+    tain_t deadline ;
+    if (milli) tain_from_millisecs(&deadline, n) ;
+    else tain_uint(&deadline, n) ;
+    tain_now_g() ;
+    tain_add_g(&deadline, &deadline) ;
+    deepsleepuntil_g(&deadline) ;
+  }
+
+  pathexec0_run(argv+1, envp) ;
+  strerr_dieexec(111, argv[1]) ;
+}
diff --git a/src/skaembutils/s6-sort.c b/src/skaembutils/s6-sort.c
new file mode 100644
index 0000000..5b259b8
--- /dev/null
+++ b/src/skaembutils/s6-sort.c
@@ -0,0 +1,123 @@
+/* ISC license. */
+
+#include <stdlib.h>
+#include <errno.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/genalloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-sort [ -bcfru0 ]"
+
+typedef int strncmp_t (char const *, unsigned int, char const *) ;
+typedef strncmp_t *strncmp_t_ref ;
+typedef int qsortcmp_t (void const *, void const *) ;
+typedef qsortcmp_t *qsortcmp_t_ref ;
+
+static int flagnoblanks = 0, flagreverse = 0, flaguniq = 0 ;
+
+static int str_diffb_f (register char const *s1, register unsigned int n, register char const *s2)
+{
+  return str_diffb(s1, n, s2) ;
+}
+
+static strncmp_t_ref comp = &str_diffb_f ;
+
+static int compit (register char const *s1, register unsigned int n1, register char const *s2, register unsigned int n2)
+{
+  register int r ;
+  if (flagnoblanks)
+  {
+    while ((*s1 == ' ') || (*s1 == '\t')) (s1++, n1--) ;
+    while ((*s2 == ' ') || (*s2 == '\t')) (s2++, n2--) ;
+  }
+  r = (*comp)(s1, n1 < n2 ? n1 : n2, s2) ;
+  if (!r) r = n1 - n2 ;
+  return flagreverse ? -r : r ;
+}
+
+static int sacmp (stralloc const *a, stralloc const *b)
+{
+  return compit(a->s, a->len - 1, b->s, b->len - 1) ;
+}
+
+static int slurplines (genalloc *lines, char sep)
+{
+  unsigned int i = 0 ;
+  for (;; i++)
+  {
+    stralloc sa = STRALLOC_ZERO ;
+    int r = skagetln(buffer_0, &sa, sep) ;
+    if (!r) break ;
+    if ((r < 0) && ((errno != EPIPE) || !stralloc_catb(&sa, &sep, 1)))
+      return -1 ;
+    stralloc_shrink(&sa) ;
+    if (!genalloc_append(stralloc, lines, &sa)) return -1 ;
+  }
+  return (int)i ;
+}
+
+static void uniq (genalloc *lines)
+{
+  unsigned int len = genalloc_len(stralloc, lines) ;
+  register stralloc *s = genalloc_s(stralloc, lines) ;
+  register unsigned int i = 1 ;
+  for (; i < len ; i++)
+    if (!sacmp(s+i-1, s+i)) stralloc_free(s+i-1) ;
+}
+
+static int outputlines (stralloc const *s, unsigned int len)
+{
+  register unsigned int i = 0 ;
+  for (; i < len ; i++)
+    if (buffer_put(buffer_1, s[i].s, s[i].len) < 0) return 0 ;
+  return buffer_flush(buffer_1) ;
+}
+
+static int check (stralloc const *s, unsigned int len)
+{
+  register unsigned int i = 1 ;
+  for (; i < len ; i++)
+    if (sacmp(s+i-1, s+i) >= !flaguniq) return 0 ;
+  return 1 ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  genalloc lines = GENALLOC_ZERO ; /* array of stralloc */
+  char sep = '\n' ;
+  int flagcheck = 0 ;
+  PROG = "s6-sort" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "bcfru0", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'b' : flagnoblanks = 1 ; break ;
+        case 'c' : flagcheck = 1 ; break ;
+        case 'f' : comp = &case_diffb ; break ;
+        case 'r' : flagreverse = 1 ; break ;
+        case 'u' : flaguniq = 1 ; break ;
+        case '0' : sep = '\0' ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  if (slurplines(&lines, sep) < 0) strerr_diefu1sys(111, "read from stdin") ;
+  if (flagcheck) return !check(genalloc_s(stralloc, &lines), genalloc_len(stralloc, &lines)) ;
+  qsort(genalloc_s(stralloc, &lines), genalloc_len(stralloc, &lines), sizeof(stralloc), (qsortcmp_t_ref)&sacmp) ;
+  if (flaguniq) uniq(&lines) ;
+  if (!outputlines(genalloc_s(stralloc, &lines), genalloc_len(stralloc, &lines)))
+    strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-sync.c b/src/skaembutils/s6-sync.c
new file mode 100644
index 0000000..a8829cd
--- /dev/null
+++ b/src/skaembutils/s6-sync.c
@@ -0,0 +1,9 @@
+/* ISC license. */
+
+#include <unistd.h>
+
+int main (void)
+{
+  sync() ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-tail.c b/src/skaembutils/s6-tail.c
new file mode 100644
index 0000000..cc2d1f1
--- /dev/null
+++ b/src/skaembutils/s6-tail.c
@@ -0,0 +1,200 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/skamisc.h>
+#include <skalibs/siovec.h>
+
+#define USAGE "s6-tail [ -c chars | -n lines | -1..9 ] [ file ]"
+
+typedef int tailfunc_t (int, unsigned int) ;
+typedef tailfunc_t *tailfunc_t_ref ;
+
+static int pluslines (int fd, unsigned int n)
+{
+  if (n) n-- ;
+  {
+    char buf[BUFFER_INSIZE] ;
+    buffer b = BUFFER_INIT(&buffer_read, fd, buf, BUFFER_INSIZE) ;
+    unsigned int count = 0 ;
+    while (count < n)
+    {
+      register int r = buffer_fill(&b) ;
+      if (r <= 0) return !r ;
+      while (!buffer_isempty(&b) && (count < n))
+      {
+        siovec_t v[2] ;
+        unsigned int i ;
+        buffer_rpeek(&b, v) ;
+        i = siovec_bytechr(v, 2, '\n') ;
+        if (i < buffer_len(&b))
+        {
+          count++ ; i++ ;
+        }
+        buffer_rseek(&b, i) ;
+      }
+    }
+    b.op = &buffer_write ;
+    b.fd = 1 ;
+    if (!buffer_flush(&b)) return 0 ;
+  }
+  return (fd_cat(fd, 1) >= 0) ;
+}
+
+static int pluschars (int fd, unsigned int n)
+{
+  if (n-- > 1)
+  {
+    int nil = open_write("/dev/null") ;
+    if (nil < 0) return 0 ;
+    if (!fd_catn(fd, nil, n))
+    {
+      register int e = errno ;
+      fd_close(nil) ;
+      errno = e ;
+      return 0 ;
+    }
+    fd_close(nil) ;
+  }
+  return (fd_cat(fd, 1) >= 0) ;
+}
+
+static int minuslines (int fd, unsigned int n)
+{
+  char buf[BUFFER_INSIZE] ;
+  buffer b = BUFFER_INIT(&buffer_read, fd, buf, BUFFER_INSIZE) ;
+  unsigned int head = 0, tail = 0 ;
+  stralloc tab[n+1] ;
+  for (; head <= n ; head++) tab[head] = stralloc_zero ;
+  head = 0 ;
+  for (;;)
+  {
+    register int r ;
+    r = skagetln(&b, tab + tail, '\n') ;
+    if (!r) break ;
+    if (r < 0)
+    {
+      if (errno == EPIPE) break ;
+      else goto err ;
+    }
+    tail = (tail + 1) % (n+1) ;
+    if (tail == head)
+    {
+      tab[head].len = 0 ;
+      head = (head + 1) % (n+1) ;
+    }
+  }
+  buffer_init(&b, &buffer_write, 1, buf, BUFFER_INSIZE) ;
+  for (; head != tail ; head = (head + 1) % (n+1))
+  {
+    if (buffer_put(&b, tab[head].s, tab[head].len) < tab[head].len)
+      goto err ;
+  }
+  for (head = 0 ; head <= n ; head++) stralloc_free(tab + head) ;
+  return buffer_flush(&b) ;
+ err:
+  for (head = 0 ; head <= n ; head++) stralloc_free(tab + head) ;
+  return 0 ;
+}
+
+static int minuschars (int fd, unsigned int n)
+{
+  char buf[BUFFER_INSIZE + n] ;
+  buffer b = BUFFER_INIT(&buffer_read, fd, buf, BUFFER_INSIZE + n) ;
+  for (;;)
+  {
+    register int r = buffer_fill(&b) ;
+    if (!r) break ;
+    if (r < 0) return 0 ;
+    buffer_rseek(&b, buffer_len(&b)) ;
+    buffer_unget(&b, n) ;
+  }
+  b.op = &buffer_write ;
+  b.fd = 1 ;
+  return buffer_flush(&b) ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  tailfunc_t_ref f = &minuslines ;
+  unsigned int n = 10 ;
+  int gotit = 0 ;
+  PROG = "s6-tail" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "123456789n:c:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case '1' :
+        case '2' :
+        case '3' :
+        case '4' :
+        case '5' :
+        case '6' :
+        case '7' :
+        case '8' :
+        case '9' :
+        {
+          if (gotit) strerr_dieusage(100, USAGE) ;
+          gotit = 1 ;
+          f = &minuslines ;
+          n = opt - '0' ;
+          break ;
+        }
+        case 'n':
+        {
+          if (gotit) strerr_dieusage(100, USAGE) ;
+          gotit = 1 ;
+          f = &minuslines ;
+          if (*l.arg == '-') l.arg++ ;
+          else if (*l.arg == '+')
+          {
+            f = &pluslines ;
+            l.arg++ ;
+          }
+          if (!uint0_scan(l.arg, &n)) strerr_dieusage(100, USAGE) ;
+          break ;
+        }
+        case 'c':
+        {
+          if (gotit) strerr_dieusage(100, USAGE) ;
+          gotit = 1 ;
+          f = &minuschars ;
+          if (*l.arg == '-') l.arg++ ;
+          else if (*l.arg == '+')
+          {
+            f = &pluschars ;
+            l.arg++ ;
+          }
+          if (!uint0_scan(l.arg, &n)) strerr_dieusage(100, USAGE) ;
+          break ;
+        }
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc)
+  {
+    if (!(*f)(0, n))
+      strerr_diefu1sys(111, "tail stdin") ;
+  }
+  else
+  {
+    int fd = open_readb(argv[0]) ;
+    if (fd == -1) strerr_diefu3sys(111, "open ", argv[0], " for reading") ;
+    if (!(*f)(fd, n))
+      strerr_diefu2sys(111, "tail ", argv[0]) ;
+    fd_close(fd) ;
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-test.c b/src/skaembutils/s6-test.c
new file mode 100644
index 0000000..3dda0b7
--- /dev/null
+++ b/src/skaembutils/s6-test.c
@@ -0,0 +1,515 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <skalibs/uint.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/fmtscan.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-test expression  or  [ expression ]"
+
+enum opnum
+{
+  T_NOT,
+  T_AND,
+  T_OR,
+  T_LEFTP,
+  T_RIGHTP,
+  T_BLOCK,
+  T_CHAR,
+  T_DIR,
+  T_EXIST,
+  T_REGULAR,
+  T_SGID,
+  T_SYMLINK,
+  T_STICKY,
+  T_NONZERO,
+  T_FIFO,
+  T_READABLE,
+  T_NONZEROFILE,
+  T_TERM,
+  T_SUID,
+  T_WRITABLE,
+  T_EXECUTABLE,
+  T_ZERO,
+  T_EUID,
+  T_EGID,
+  T_SOCKET,
+  T_MODIFIED,
+  T_NEWER,
+  T_OLDER,
+  T_DEVINO,
+  T_STREQUAL,
+  T_STRNEQUAL,
+  T_STRLESSER,
+  T_STRLESSERE,
+  T_STRGREATER,
+  T_STRGREATERE,
+  T_NUMEQUAL,
+  T_NUMNEQUAL,
+  T_NUMGREATER,
+  T_NUMGREATERE,
+  T_NUMLESSER,
+  T_NUMLESSERE
+} ;
+
+struct token
+{
+  char const *string ;
+  enum opnum op ;
+  unsigned int type ;
+} ;
+
+struct node
+{
+  enum opnum op ;
+  unsigned int type ;
+  unsigned int arg1 ;
+  unsigned int arg2 ;
+  char const *data ;
+} ;
+
+static unsigned int lex (struct node *tree, char const *const *argv)
+{
+  static struct token const tokens[44] =
+  {
+    { "-n", T_NONZERO, 2 },
+    { "-z", T_ZERO, 2 },
+    { "=", T_STREQUAL, 3 },
+    { "!=", T_STRNEQUAL, 3 },
+    { "-eq", T_NUMEQUAL, 3 },
+    { "-ne", T_NUMNEQUAL, 3 },
+    { "-gt", T_NUMGREATER, 3 },
+    { "-ge", T_NUMGREATERE, 3 },
+    { "-lt", T_NUMLESSER, 3 },
+    { "-le", T_NUMLESSERE, 3 },
+    { "-f", T_REGULAR, 2 },
+    { "-h", T_SYMLINK, 2 },
+    { "-L", T_SYMLINK, 2 },
+    { "-e", T_EXIST, 2 },
+    { "-k", T_STICKY, 2 },
+    { "-a", T_AND, 7 },
+    { "-o", T_OR, 8 },
+    { "!", T_NOT, 6 },
+    { "(", T_LEFTP, 4 },
+    { ")", T_RIGHTP, 5 },
+    { "-b", T_BLOCK, 2 },
+    { "-c", T_CHAR, 2 },
+    { "-d", T_DIR, 2 },
+    { "-g", T_SGID, 2 },
+    { "-p", T_FIFO, 2 },
+    { "-r", T_READABLE, 2 },
+    { "-s", T_NONZEROFILE, 2 },
+    { "-t", T_TERM, 2 },
+    { "-u", T_SUID, 2 },
+    { "-w", T_WRITABLE, 2 },
+    { "-x", T_EXECUTABLE, 2 },
+    { "-O", T_EUID, 2 },
+    { "-U", T_EUID, 2 },
+    { "-G", T_EGID, 2 },
+    { "-S", T_SOCKET, 2 },
+    { "-N", T_MODIFIED, 2 },
+    { "-nt", T_NEWER, 3 },
+    { "-ot", T_OLDER, 3 },
+    { "-ef", T_DEVINO, 3 },
+    { "<", T_STRLESSER, 3 },
+    { "<=", T_STRLESSERE, 3 },
+    { ">", T_STRGREATER, 3 },
+    { ">=", T_STRGREATERE, 3 },
+    { 0, 0, 0 }
+  } ;
+  register unsigned int pos = 0 ;
+
+  for (; argv[pos] ; pos++)
+  {
+    unsigned int i = 0 ;
+    tree[pos].data = argv[pos] ;
+    for (i = 0 ; tokens[i].string ; i++)
+      if (!str_diff(argv[pos], tokens[i].string))
+      {
+        tree[pos].op = tokens[i].op ;
+        tree[pos].type = tokens[i].type ;
+        break ;
+      }
+    if (!tokens[i].string)
+    {
+      tree[pos].op = T_NONZERO ;
+      tree[pos].type = 0 ;
+      tree[pos].arg1 = pos ;
+      if (*(argv[pos]) == '\\') tree[pos].data++ ; /* better than SUSv3 */
+    }
+  }
+  return pos ;
+}
+
+static unsigned int parse (struct node *tree, unsigned int n)
+{
+  static char const table[9][13] =
+  {
+    "xssssxsssxxxx",
+    "xxxxxaxxxxxxx",
+    "xsxxsxsssxxxx",
+    "sxxxxxxxxxxxx",
+    "xsxxsxsssxxxx",
+    "nxxxxNxxxAOEs",
+    "xsxxsxsssxxxx",
+    "nxxxxNxxxAsxx",
+    "nxxxxNxxxAOsx"
+  } ;
+
+  unsigned int stack[n+2] ;
+  unsigned int sp = 0, pos = 0 ;
+  int cont = 1 ;
+
+  stack[0] = n+1 ;
+  tree[n].type = 5 ; /* add ) for the final reduce */
+  tree[n+1].type = 1 ; /* add EOF */
+
+  while (cont)
+  {
+    switch (table[tree[pos].type][tree[stack[sp]].type])
+    {
+      case 'x' : /* error */
+      {
+        char fmt[UINT_FMT] ;
+        fmt[uint_fmt(fmt, pos)] = 0 ;
+        strerr_dief2x(100, "parse error at argument ", fmt) ;
+        break ;
+      }
+      case 'a' : /* accept */
+      {
+        cont = 0 ;
+        break ;
+      }
+      case 's' : /* shift */
+      {
+        stack[++sp] = pos++ ;
+        break ;
+      }
+      case 'n' : /* reduce -> expr without nots, from atom */
+      {
+        switch (tree[stack[sp-1]].type)
+        {
+          case 2 :
+          {
+            tree[stack[sp-1]].arg1 = stack[sp] ;
+            sp-- ;
+            break ;
+          }
+          case 3 :
+          {
+            tree[stack[sp-1]].arg1 = stack[sp-2] ;
+            tree[stack[sp-1]].arg2 = stack[sp] ;
+            stack[sp-2] = stack[sp-1] ;
+            sp -= 2 ;
+            break ;
+          }
+          /* default : assert: its a zero */
+        }
+        tree[stack[sp]].type = 9 ;
+        while (tree[stack[sp-1]].type == 6)
+        {
+          tree[stack[sp-1]].type = 9 ;
+          tree[stack[sp-1]].arg1 = stack[sp] ;
+          sp-- ;
+        }
+        break ;
+      }
+      case 'N' : /* reduce -> expr without nots, from expr */
+      {
+        if (tree[stack[sp-2]].type != 4)
+        {
+          char fmt[UINT_FMT] ;
+          fmt[uint_fmt(fmt, pos)] = 0 ;
+          strerr_dief2x(100, "parse error: bad right parenthesis at argument ", fmt) ;
+        }
+        stack[sp-2] = stack[sp-1] ;
+        sp -= 2 ;
+        tree[stack[sp]].type = 9 ;
+        while (tree[stack[sp-1]].type == 6)
+        {
+          tree[stack[sp-1]].type = 9 ;
+          tree[stack[sp-1]].arg1 = stack[sp] ;
+          sp-- ;
+        }
+        break ;
+      }
+      case 'A' : /* reduce -> exprs without ands */
+      {
+        if (tree[stack[sp-1]].type == 7)
+        {
+          tree[stack[sp-1]].arg1 = stack[sp-2] ;
+          tree[stack[sp-1]].arg2 = stack[sp] ;
+          stack[sp-2] = stack[sp-1] ;
+          sp -= 2 ;
+        }
+        tree[stack[sp]].type = 10 ;
+        break ;
+      }
+      case 'O' : /* reduce -> expr without ors */
+      {
+        if (tree[stack[sp-1]].type == 8)
+        {
+          tree[stack[sp-1]].arg1 = stack[sp-2] ;
+          tree[stack[sp-1]].arg2 = stack[sp] ;
+          stack[sp-2] = stack[sp-1] ;
+          sp -= 2 ;
+        }
+        tree[stack[sp]].type = 11 ;
+        break ;
+      }
+      case 'E' : /* reduce -> expr */
+      {
+        tree[stack[sp]].type = 12 ;
+        break ;
+      }
+      default : /* can't happen */
+        strerr_dief1x(101, "internal error, please submit a bug-report.") ;
+    }
+  }
+  if (sp != 2) strerr_dief1x(100, "parse error: too many left parentheses") ;
+  return stack[1] ;
+}
+
+static int run (struct node const *tree, unsigned int root)
+{
+  switch (tree[root].op)
+  {
+    case T_NOT :
+      return !run(tree, tree[root].arg1) ;
+    case T_AND :
+      return run(tree, tree[root].arg1) && run(tree, tree[root].arg2) ;
+    case T_OR :
+      return run(tree, tree[root].arg1) || run(tree, tree[root].arg2) ;
+    case T_EXIST :
+    {
+      struct stat st ;
+      return !stat(tree[tree[root].arg1].data, &st) ;
+    }
+    case T_BLOCK :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISBLK(st.st_mode) ;
+    }
+    case T_CHAR :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISCHR(st.st_mode) ;
+    }
+    case T_DIR :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISDIR(st.st_mode) ;
+    }
+    case T_REGULAR :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISREG(st.st_mode) ;
+    }
+    case T_FIFO :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISFIFO(st.st_mode) ;
+    }
+    case T_SOCKET :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISSOCK(st.st_mode) ;
+    }
+    case T_SYMLINK :
+    {
+      struct stat st ;
+      if (lstat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return S_ISLNK(st.st_mode) ;
+    }
+    case T_SGID :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return (st.st_mode & S_ISGID) ;
+    }
+    case T_SUID :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return (st.st_mode & S_ISUID) ;
+    }
+    case T_STICKY :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return (st.st_mode & S_ISVTX) ;
+    }
+    case T_NONZEROFILE :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return (st.st_size > 0) ;
+    }
+    case T_MODIFIED :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return (st.st_mtime > st.st_atime) ;
+    }
+    case T_EUID :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return st.st_uid == geteuid() ;
+    }
+    case T_EGID :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      return st.st_gid == getegid() ;
+    }
+    case T_READABLE :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      if (st.st_uid == geteuid()) return st.st_mode & S_IRUSR ;
+      else if (st.st_gid == getegid()) return st.st_mode & S_IRGRP ;
+      else return st.st_mode & S_IROTH ;
+    }
+    case T_WRITABLE :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      if (st.st_uid == geteuid()) return st.st_mode & S_IWUSR ;
+      else if (st.st_gid == getegid()) return st.st_mode & S_IWGRP ;
+      else return st.st_mode & S_IWOTH ;
+    }
+    case T_EXECUTABLE :
+    {
+      struct stat st ;
+      if (stat(tree[tree[root].arg1].data, &st) == -1) return 0 ;
+      if (st.st_uid == geteuid()) return st.st_mode & S_IXUSR ;
+      else if (st.st_gid == getegid()) return st.st_mode & S_IXGRP ;
+      else return st.st_mode & S_IXOTH ;
+    }
+    case T_NEWER :
+    {
+      struct stat st1, st2 ;
+      if (stat(tree[tree[root].arg1].data, &st1) == -1) return 0 ;
+      if (stat(tree[tree[root].arg2].data, &st2) == -1) return 1 ;
+      return st1.st_mtime > st2.st_mtime ;
+    }
+    case T_OLDER :
+    {
+      struct stat st1, st2 ;
+      if (stat(tree[tree[root].arg1].data, &st1) == -1) return 1 ;
+      if (stat(tree[tree[root].arg2].data, &st2) == -1) return 0 ;
+      return st1.st_mtime < st2.st_mtime ;
+    }
+    case T_DEVINO :
+    {
+      struct stat st1, st2 ;
+      if (stat(tree[tree[root].arg1].data, &st1) == -1) return 0 ;
+      if (stat(tree[tree[root].arg2].data, &st2) == -1) return 1 ;
+      return (st1.st_dev == st2.st_dev) && (st1.st_ino == st2.st_ino) ;
+    }
+    case T_TERM :
+    {
+      unsigned int fd ;
+      if (!uint0_scan(tree[tree[root].arg1].data, &fd))
+        strerr_dief2x(100, tree[root].data, " requires an integer argument") ;
+      return isatty((int)fd) ;
+    }
+    case T_NONZERO :
+      return tree[tree[root].arg1].data[0] ;
+    case T_ZERO :
+      return !tree[tree[root].arg1].data[0] ;
+    case T_STREQUAL :
+      return !str_diff(tree[tree[root].arg1].data, tree[tree[root].arg2].data) ;
+    case T_STRNEQUAL :
+      return !!str_diff(tree[tree[root].arg1].data, tree[tree[root].arg2].data) ;
+    case T_STRLESSER :
+      return str_diff(tree[tree[root].arg1].data, tree[tree[root].arg2].data) < 0 ;
+    case T_STRLESSERE :
+      return str_diff(tree[tree[root].arg1].data, tree[tree[root].arg2].data) <= 0 ;
+    case T_STRGREATER :
+      return str_diff(tree[tree[root].arg1].data, tree[tree[root].arg2].data) > 0 ;
+    case T_STRGREATERE :
+      return str_diff(tree[tree[root].arg1].data, tree[tree[root].arg2].data) >= 0 ;
+    case T_NUMEQUAL :
+    {
+      int n1, n2 ;
+      if (!int_scan(tree[tree[root].arg1].data, &n1)
+       || !int_scan(tree[tree[root].arg2].data, &n2))
+        goto errorint ;
+      return n1 == n2 ;
+    }
+    case T_NUMNEQUAL :
+    {
+      int n1, n2 ;
+      if (!int_scan(tree[tree[root].arg1].data, &n1)
+       || !int_scan(tree[tree[root].arg2].data, &n2))
+        goto errorint ;
+      return n1 != n2 ;
+    }
+    case T_NUMGREATER :
+    {
+      int n1, n2 ;
+      if (!int_scan(tree[tree[root].arg1].data, &n1)
+       || !int_scan(tree[tree[root].arg2].data, &n2))
+        goto errorint ;
+      return n1 > n2 ;
+    }
+    case T_NUMGREATERE :
+    {
+      int n1, n2 ;
+      if (!int_scan(tree[tree[root].arg1].data, &n1)
+       || !int_scan(tree[tree[root].arg2].data, &n2))
+        goto errorint ;
+      return n1 >= n2 ;
+    }
+    case T_NUMLESSER :
+    {
+      int n1, n2 ;
+      if (!int_scan(tree[tree[root].arg1].data, &n1)
+       || !int_scan(tree[tree[root].arg2].data, &n2))
+        goto errorint ;
+      return n1 < n2 ;
+    }
+    case T_NUMLESSERE :
+    {
+      int n1, n2 ;
+      if (!int_scan(tree[tree[root].arg1].data, &n1)
+       || !int_scan(tree[tree[root].arg2].data, &n2))
+        goto errorint ;
+      return n1 <= n2 ;
+    }
+    default:
+      strerr_dief1x(111, "operation not implemented") ;
+  }
+
+errorint:
+  strerr_dief2x(100, tree[root].data, " requires integer arguments") ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  PROG = "s6-test" ;
+  if (argc <= 1) return 1 ;
+  {
+    struct node tree[argc + 2] ;    
+    unsigned int n = lex(tree, argv+1) ;
+    if ((argv[0][0] == '[') && !argv[0][1])
+    {
+      if (n && (!tree[n-1].type) && (tree[n-1].data[0] == ']') && !tree[n-1].data[1])
+        n-- ;
+      else strerr_dief1x(100, "parse error: missing closing bracket") ;
+    }
+    return !run(tree, parse(tree, n)) ;
+  }
+}
diff --git a/src/skaembutils/s6-touch.c b/src/skaembutils/s6-touch.c
new file mode 100644
index 0000000..b149835
--- /dev/null
+++ b/src/skaembutils/s6-touch.c
@@ -0,0 +1,20 @@
+/* ISC license. */
+
+#include <skalibs/strerr2.h>
+#include <skalibs/djbunix.h>
+
+#define USAGE "s6-touch file ..."
+
+int main (int argc, char const *const *argv)
+{
+  char const *const *p = argv + 1 ;
+  PROG = "s6-touch" ;
+  if (argc < 2) strerr_dieusage(100, USAGE) ;
+  for (; *p ; p++)
+  {
+    register int fd = open_append(*p) ;
+    if (fd < 0) strerr_diefu2sys(111, "open_append ", *p) ;
+    fd_close(fd) ;
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-true.c b/src/skaembutils/s6-true.c
new file mode 100644
index 0000000..65c3af4
--- /dev/null
+++ b/src/skaembutils/s6-true.c
@@ -0,0 +1,6 @@
+/* ISC license. */
+
+int main ()
+{
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-uniquename.c b/src/skaembutils/s6-uniquename.c
new file mode 100644
index 0000000..06418e5
--- /dev/null
+++ b/src/skaembutils/s6-uniquename.c
@@ -0,0 +1,40 @@
+/* ISC license. */
+
+#include <skalibs/allreadwrite.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/skamisc.h>
+#include <skalibs/random.h>
+
+#define USAGE "s6-uniquename [ -n randomlen ] prefix"
+#define usage() strerr_dieusage(100, USAGE)
+
+int main (int argc, char const *const *argv)
+{
+  stralloc sa = STRALLOC_ZERO ;
+  unsigned int n = 8 ;
+  PROG = "s6-uniquename" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "n:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n' : if (!uint0_scan(l.arg, &n)) usage() ; break ;
+        default : usage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (argc < 1) usage() ;
+  if (!stralloc_cats(&sa, argv[0])) strerr_diefu1sys(111, "stralloc_cats") ;
+  if ((n ? random_sauniquename(&sa, n) : sauniquename(&sa)) < 0)
+    strerr_diefu1sys(111, "make unique name") ;
+  if (!stralloc_catb(&sa, "\n", 1)) strerr_diefu1sys(111, "stralloc_cats") ;
+  if (allwrite(1, sa.s, sa.len) < sa.len) strerr_diefu1sys(111, "write to stdout") ;
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-unquote-filter.c b/src/skaembutils/s6-unquote-filter.c
new file mode 100644
index 0000000..08477ef
--- /dev/null
+++ b/src/skaembutils/s6-unquote-filter.c
@@ -0,0 +1,198 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/buffer.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-unquote-filter [ -q | -Q | -v | -w ] [ -d delim ]"
+
+static unsigned int strictness = 1 ;
+static char const *delim = "\"" ;
+static unsigned int delimlen = 1 ;
+
+static void fillfmt (char *fmt, char const *s, unsigned int len)
+{
+  register unsigned int n = len < 39 ? len+1 : 36 ;
+  byte_copy(fmt, n, s) ;
+  if (len >= 39)
+  {
+    byte_copy(fmt+n, 3, "...") ;
+    n += 3 ;
+  }
+  fmt[n] = 0 ;
+}
+
+static int doit (char const *s, unsigned int len)
+{
+  if (delimlen)
+  {
+    if (!len)
+    {
+      switch (strictness)
+      {
+        case 1 :
+        case 2 :
+          strerr_warnw1x("empty line") ;
+          break ;
+        case 3 :
+          buffer_flush(buffer_1) ;
+          strerr_dief1x(100, "empty line") ;
+        default : break ;
+      }
+      return 1 ;
+    }
+    if (byte_chr(delim, delimlen, *s) >= delimlen)
+    {
+      switch (strictness)
+      {
+        case 0 : return 0 ;
+        case 1 :
+        {
+          strerr_warnw1x("invalid starting quote character") ;
+          return 0 ;
+        }
+        case 2 :
+        {
+          char fmt[40] ;
+          fillfmt(fmt, s, len) ;
+          strerr_warnw3x("invalid starting quote character", " in line: ", fmt) ;
+          return 0 ;
+        }
+        case 3 :
+        {
+          buffer_flush(buffer_1) ;
+          strerr_dief1x(100, "invalid starting quote character") ;
+        }
+        default : strerr_dief1x(101, "can't happen: unknown strictness") ;
+      }
+    }
+  }
+  {
+    unsigned int r, w ;
+    char d[len] ;
+    if (!string_unquote_withdelim(d, &w, s + !!delimlen, len - !!delimlen, &r, delim, delimlen))
+    {
+      switch (strictness)
+      {
+        case 0 : return 0 ;
+        case 1 :
+        {
+          strerr_warnwu1sys("unquote") ;
+          return 0 ;
+        }
+        case 2 :
+        {
+          char fmt[40] ;
+          fillfmt(fmt, s, len) ;
+          strerr_warnwu3sys("unquote", " line: ", fmt) ;
+          return 0 ;
+        }
+        case 3 :
+        {
+          int e = errno ;
+          buffer_flush(buffer_1) ;
+          errno = e ;
+          strerr_diefu1sys(100, "unquote") ;
+        }
+        default : strerr_dief1x(101, "can't happen: unknown strictness") ;
+      }
+    }
+    if (delimlen)
+    {
+      if (r+1 == len)
+      {
+        switch (strictness)
+        {
+          case 0 : return 0 ;
+          case 1 :
+          {
+            strerr_warnwu2x("unquote", ": no ending quote character") ;
+            return 0 ;
+          }
+          case 2 :
+          {
+            char fmt[40] ;
+            fillfmt(fmt, s, len) ;
+            strerr_warnwu5x("unquote", ": no ending quote character", " in ", "line: ", fmt) ;
+            return 0 ;
+          }
+          case 3 :
+          {
+            int e = errno ;
+            buffer_flush(buffer_1) ;
+            errno = e ;
+            strerr_diefu2x(100, "unquote", ": no ending quote character") ;
+          }
+          default : strerr_dief1x(101, "can't happen: unknown strictness") ;
+        }
+      }
+      else if ((r+2 < len) && (strictness >= 2))
+      {
+        char fmtnum[UINT_FMT] ;
+        char fmtden[UINT_FMT] ;
+        char fmt[40] ;
+        fillfmt(fmt, s, len) ;
+        fmtnum[uint_fmt(fmtnum, r+1)] = 0 ;
+        fmtden[uint_fmt(fmtden, len-1)] = 0 ;
+        strerr_warnw7x("found ending quote character at position ", fmtnum, "/", fmtden, ", ignoring remainder of ", "line: ", fmt) ;
+      }
+    }
+    if (buffer_put(buffer_1, d, w) < (int)w)
+      strerr_diefu1sys(111, "write to stdout") ;
+  }
+  return 1 ;
+}
+
+
+int main (int argc, char const *const *argv)
+{
+  stralloc src = STRALLOC_ZERO ;
+  PROG = "s6-unquote-filter" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "qQvwd:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'q': strictness = 0 ; break ;
+        case 'Q': strictness = 1 ; break ;
+        case 'v': strictness = 2 ; break ;
+        case 'w': strictness = 3 ; break ;
+        case 'd': delim = l.arg ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  delimlen = str_len(delim) ;
+  for (;;)
+  {
+    int r ;
+    src.len = 0 ;
+    r = skagetln(buffer_0f1, &src, '\n') ;
+    if (!r) break ;
+    if (r < 0)
+    {
+      if (errno != EPIPE) strerr_diefu1sys(111, "read from stdin") ;
+    }
+    else src.len-- ;
+    if (!doit(src.s, src.len))
+    {
+      if (buffer_put(buffer_1, src.s, src.len) < (int)src.len)
+        strerr_diefu1sys(111, "write to stdout") ;
+    }
+    if (r > 0)
+    {
+      if (buffer_put(buffer_1, "\n", 1) < 1)
+        strerr_diefu1sys(111, "write to stdout") ;
+    }
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-unquote.c b/src/skaembutils/s6-unquote.c
new file mode 100644
index 0000000..37c3dfb
--- /dev/null
+++ b/src/skaembutils/s6-unquote.c
@@ -0,0 +1,70 @@
+/* ISC license. */
+
+#include <skalibs/sgetopt.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/uint.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/skamisc.h>
+
+#define USAGE "s6-unquote [ -n ] [ -d delim ] string"
+
+int main (int argc, char const *const *argv)
+{
+  char const *delim = "\"" ;
+  unsigned int len, delimlen ;
+  int nl = 1 ;
+  char const *string ;
+  PROG = "s6-unquote" ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      register int opt = subgetopt_r(argc, argv, "nd:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'n' : nl = 0 ; break ;
+        case 'd': delim = l.arg ; break ;
+        default : strerr_dieusage(100, USAGE) ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (!argc) strerr_dieusage(100, USAGE) ;
+  string = *argv ;
+  len = str_len(string) ;
+  delimlen = str_len(delim) ;
+  if (delimlen)
+  {
+    if (!len--) strerr_dief1x(100, "the empty string isn't a quoted string") ;
+    if (byte_chr(delim, delimlen, *string++) >= delimlen)
+      strerr_dief1x(100, "invalid starting quote character") ;
+  }
+  {
+    unsigned int r = 0, w = 0 ;
+    char buf[len+1] ;
+    if (!string_unquote_withdelim(buf, &w, string, len, &r, delim, delimlen))
+    {
+      char fmt[UINT_FMT] ;
+      fmt[uint_fmt(fmt, r + !!delimlen)] = 0 ;
+      strerr_diefu2sys(100, "unquote at character ", fmt) ;
+    }
+    if (delimlen)
+    {
+      if (r == len) strerr_dief1x(100, "no ending quote character") ;
+      else if (r < len - 1)
+      {
+        char fmtnum[UINT_FMT] ;
+        char fmtden[UINT_FMT] ;
+        fmtnum[uint_fmt(fmtnum, r+1)] = 0 ;
+        fmtden[uint_fmt(fmtden, len)] = 0 ;
+        strerr_warnw5x("found ending quote character at position ", fmtnum, "/", fmtden, "; ignoring remainder") ;
+      }
+    }
+    if (nl) buf[w++] = '\n' ;
+    if (allwrite(1, buf, w) < w)
+      strerr_diefu1sys(111, "write to stdout") ;
+  }
+  return 0 ;
+}
diff --git a/src/skaembutils/s6-update-symlinks.c b/src/skaembutils/s6-update-symlinks.c
new file mode 100644
index 0000000..ba89b06
--- /dev/null
+++ b/src/skaembutils/s6-update-symlinks.c
@@ -0,0 +1,367 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/direntry.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/random.h>
+
+#define USAGE "s6-update-symlinks /destdir /srcdir [ /srcdir ... ]"
+
+#define MAGICNEW ":s6-update-symlinks-new"
+#define MAGICOLD ":s6-update-symlinks-old"
+
+#define CONFLICT -2
+#define ERROR -1
+#define MODIFIED 0
+#define OVERRIDEN 1
+
+static stralloc errdst = STRALLOC_ZERO ;
+static stralloc errsrc = STRALLOC_ZERO ;
+
+
+typedef struct stralloc3 stralloc3, *stralloc3_ref ;
+struct stralloc3
+{
+  stralloc dst ;
+  stralloc src ;
+  stralloc tmp ;
+} ;
+
+#define STRALLOC3_ZERO { STRALLOC_ZERO, STRALLOC_ZERO, STRALLOC_ZERO }
+
+
+static void cleanup (stralloc *sa, unsigned int pos)
+{
+  register int e = errno ;
+  rm_rf_in_tmp(sa, pos) ;
+  errno = e ;
+}
+
+
+static int makeuniquename (stralloc *sa, char const *path, char const *magic)
+{
+  unsigned int base = sa->len ;
+  int wasnull = !sa->s ;
+  if (!stralloc_cats(sa, path)) return 0 ;
+  if (!stralloc_cats(sa, magic)) goto err ;
+  if (random_sauniquename(sa, 8) == -1) goto err ;
+  if (!stralloc_0(sa)) goto err ;
+  return 1 ;
+
+err:
+  if (wasnull) stralloc_free(sa) ; else sa->len = base ;
+  return 0 ;
+}
+
+
+static int addlink (stralloc3 *blah, unsigned int dstpos, unsigned int srcpos)
+{
+  if (symlink(blah->src.s + srcpos, blah->dst.s + dstpos) >= 0) return MODIFIED ;
+  if (errno != EEXIST) return ERROR ;
+
+  {
+    unsigned int dstbase = blah->dst.len ;
+    unsigned int srcbase = blah->src.len ;
+    unsigned int tmpbase = blah->tmp.len ;
+    unsigned int dststop ;
+    unsigned int srcstop ;
+    signed int diffsize = 0 ;
+    int collect = 1 ;
+
+    {
+      register unsigned int n = str_len(blah->dst.s + dstpos) ;
+      if (!stralloc_readyplus(&blah->dst, n+1)) return ERROR ;
+      stralloc_catb(&blah->dst, blah->dst.s + dstpos, n) ;
+    }
+    stralloc_catb(&blah->dst, "/", 1) ;
+    dststop = blah->dst.len ;
+
+    {
+      int r ;
+      DIR *dir = opendir(blah->dst.s + dstpos) ;
+      if (!dir)
+      {
+        blah->dst.len = dstbase ;
+        if (errno != ENOTDIR) return ERROR ;
+        if ((unlink(blah->dst.s + dstpos) == -1)
+         || (symlink(blah->src.s + srcpos, blah->dst.s + dstpos) == -1))
+          return ERROR ;
+        return OVERRIDEN ; /* replaced a link to a normal file */
+      }
+      r = sareadlink(&blah->src, blah->dst.s + dstpos) ;
+      if ((r == -1) && (errno != EINVAL))
+      {
+        register int e = errno ;
+        blah->dst.len = dstbase ;
+        dir_close(dir) ;
+        errno = e ;
+        return ERROR ;
+      }
+      if (r < 0)
+      {
+        for (;;)
+        {
+          register direntry *d ;
+          errno = 0 ;
+          d = readdir(dir) ;
+          if (!d) break ;
+          if ((d->d_name[0] == '.') && (!d->d_name[1] || ((d->d_name[1] == '.') && !d->d_name[2])))
+            continue ;
+          diffsize-- ;  /* need to know the size for collect */
+        }
+        if (errno)
+        {
+          register int e = errno ;
+          blah->src.len = srcbase ;
+          blah->dst.len = dstbase ;
+          dir_close(dir) ;
+          errno = e ;
+          return ERROR ;
+        }
+      }
+      else if ((unlink(blah->dst.s + dstpos) == -1)
+            || (mkdir(blah->dst.s + dstpos, 0777) == -1)
+            || !stralloc_catb(&blah->src, "/", 1))
+      {
+        register int e = errno ;
+        blah->src.len = srcbase ;
+        blah->dst.len = dstbase ;
+        dir_close(dir) ;
+        errno = e ;
+        return ERROR ;
+      }
+      else         /* expand */
+      {
+        srcstop = blah->src.len ;
+        for (;;)
+        {
+          register direntry *d ;
+          errno = 0 ;
+          d = readdir(dir) ;
+          if (!d) break ;
+          if ((d->d_name[0] == '.') && (!d->d_name[1] || ((d->d_name[1] == '.') && !d->d_name[2])))
+            continue ;
+          diffsize-- ;
+          blah->dst.len = dststop ;
+          blah->src.len = srcstop ;
+          if (!stralloc_cats(&blah->dst, d->d_name) || !stralloc_0(&blah->dst)
+           || !stralloc_cats(&blah->src, d->d_name) || !stralloc_0(&blah->src)
+           || (symlink(blah->src.s + srcbase, blah->dst.s + dstbase) == -1))
+          {
+            register int e = errno ;
+            blah->src.len = srcbase ;
+            blah->dst.len = dstbase ;
+            dir_close(dir) ;
+            errno = e ;
+            return ERROR ;
+          }
+        }
+        if (errno)
+        {
+          register int e = errno ;
+          blah->src.len = srcbase ;
+          blah->dst.len = dstbase ;
+          dir_close(dir) ;
+          errno = e ;
+          return ERROR ;
+        }
+      }
+      dir_close(dir) ;
+    }
+
+    blah->src.len = srcbase ;
+    {
+      register unsigned int n = str_len(blah->src.s + srcpos) ;
+      if (!stralloc_readyplus(&blah->src, n+1))
+      {
+        blah->dst.len = dstbase ;
+        return ERROR ;
+      }
+      stralloc_catb(&blah->src, blah->src.s + srcpos, n) ;
+    }
+    stralloc_catb(&blah->src, "/", 1) ;
+    srcstop = blah->src.len ;
+
+
+   /* prepare tmp for recursion */
+
+    {
+      DIR *dir = opendir(blah->src.s + srcpos) ;
+      if (!dir)
+      {
+        blah->src.len = srcbase ;
+        blah->dst.len = dstbase ;
+        if (errno != ENOTDIR) return ERROR ;
+        errdst.len = errsrc.len = 0 ;
+        if (!stralloc_cats(&errdst, blah->dst.s + dstpos) || !stralloc_0(&errdst)
+         || !stralloc_cats(&errsrc, blah->src.s + srcpos) || !stralloc_0(&errsrc))
+          return ERROR ;
+        return CONFLICT ; /* dst is a dir but src is not */
+      }
+      for (;;)
+      {
+        register direntry *d ;
+        errno = 0 ;
+        d = readdir(dir) ;
+        if (!d) break ;
+        if ((d->d_name[0] == '.') && (!d->d_name[1] || ((d->d_name[1] == '.') && !d->d_name[2])))
+          continue ;
+        if (!stralloc_cats(&blah->tmp, d->d_name) || !stralloc_0(&blah->tmp))
+        {
+          register int e = errno ;
+          blah->tmp.len = tmpbase ;
+          blah->src.len = srcbase ;
+          blah->dst.len = dstbase ;
+          dir_close(dir) ;
+          errno = e ;
+          return ERROR ;
+        }
+      }
+      if (errno)
+      {
+        register int e = errno ;
+        blah->tmp.len = tmpbase ;
+        blah->src.len = srcbase ;
+        blah->dst.len = dstbase ;
+        dir_close(dir) ;
+        errno = e ;
+        return ERROR ;
+      }
+      dir_close(dir) ;
+    }
+
+
+   /* recurse */
+
+    {
+      unsigned int i = tmpbase ;
+      while (i < blah->tmp.len)
+      {
+        diffsize++ ;
+        blah->dst.len = dststop ;
+        blah->src.len = srcstop ;
+        {
+          register unsigned int n = str_len(blah->tmp.s + i) + 1 ;
+          if (!stralloc_catb(&blah->dst, blah->tmp.s + i, n)
+           || !stralloc_catb(&blah->src, blah->tmp.s + i, n))
+          {
+            blah->tmp.len = tmpbase ;
+            blah->src.len = srcbase ;
+            blah->dst.len = dstbase ;
+            return ERROR ;
+          }
+          i += n ;
+        }
+        switch (addlink(blah, dstbase, srcbase))
+        {
+          case ERROR :
+            blah->tmp.len = tmpbase ;
+            blah->src.len = srcbase ;
+            blah->dst.len = dstbase ;
+            return ERROR ;
+          case CONFLICT :
+            blah->tmp.len = tmpbase ;
+            blah->src.len = srcbase ;
+            blah->dst.len = dstbase ;
+            return CONFLICT ;
+          case MODIFIED :
+            collect = 0 ;
+        }
+      }
+    }
+    blah->tmp.len = tmpbase ;
+    blah->src.len = srcbase ;
+    blah->dst.len = dstbase ;
+
+
+   /* collect */
+
+    if (collect && !diffsize)
+    {
+      if (rm_rf_in_tmp(&blah->dst, dstpos) == -1) return ERROR ;
+      if (symlink(blah->src.s + srcpos, blah->dst.s + dstpos) == -1) return ERROR ;
+      return OVERRIDEN ;
+    }
+  }
+  return MODIFIED ;
+}
+
+int main (int argc, char *const *argv)
+{
+  stralloc3 blah = STRALLOC3_ZERO ;
+  PROG = "s6-update-symlinks" ;
+  if (argc < 3) strerr_dieusage(100, USAGE) ;
+  {
+    register char *const *p = argv + 1 ;
+    for (; *p ; p++) if (**p != '/') strerr_dieusage(100, USAGE) ;
+  }
+  {
+    register unsigned int i = str_len(argv[1]) ;
+    while (i && (argv[1][i-1] == '/')) argv[1][--i] = 0 ;
+    if (!i) strerr_diefu1x(100, "replace root directory") ;
+  }
+  if (!makeuniquename(&blah.dst, argv[1], MAGICNEW))
+    strerr_diefu2sys(111, "make random unique name based on ", argv[1]) ;
+  if ((unlink(blah.dst.s) == -1) && (errno != ENOENT))
+    strerr_diefu2sys(111, "unlink ", blah.dst.s) ;
+
+  {
+    char *const *p = argv + 2 ;
+    for (; *p ; p++)
+    {
+      register int r ;
+      blah.src.len = 0 ;
+      if (!stralloc_cats(&blah.src, *p) || !stralloc_0(&blah.src))
+        strerr_diefu1sys(111, "make stralloc") ;
+      r = addlink(&blah, 0, 0) ;
+      if (r < 0)
+      {
+        stralloc_free(&blah.tmp) ;
+        stralloc_free(&blah.src) ;
+        cleanup(&blah.dst, 0) ;
+        stralloc_free(&blah.dst) ;
+        if (r == CONFLICT)
+          strerr_dief4x(100, "destination ", errdst.s, " conflicts with source ", errsrc.s) ;
+        else
+          strerr_dief2sys(111, "error processing ", *p) ;
+      }
+    }
+  }
+  stralloc_free(&blah.tmp) ;
+
+  if (rename(blah.dst.s, argv[1]) == -1) /* be atomic if possible */
+  {
+    blah.src.len = 0 ;
+    if (!makeuniquename(&blah.src, argv[1], MAGICOLD))
+    {
+      cleanup(&blah.dst, 0) ;
+      strerr_diefu2sys(111, "make random unique name based on ", argv[1]) ;
+    }
+
+    if (rename(argv[1], blah.src.s) == -1)
+    {
+      cleanup(&blah.dst, 0) ;
+      strerr_diefu4sys(111, "rename ", argv[1], " to ", blah.src.s) ;
+    }
+   /* XXX: unavoidable race condition here: argv[1] does not exist */
+    if (rename(blah.dst.s, argv[1]) == -1)
+    {
+      rename(blah.src.s, argv[1]) ;
+      cleanup(&blah.dst, 0) ;
+      strerr_diefu4sys(111, "rename ", blah.dst.s, " to ", argv[1]) ;
+    }
+    stralloc_free(&blah.dst) ;
+    if (rm_rf_in_tmp(&blah.src, 0) == -1)
+      strerr_warnwu2sys("remove old directory ", blah.src.s) ;
+    stralloc_free(&blah.src) ;
+  }
+
+  return 0 ;
+}