Add -E option for variable autoimport

15 files changed, 268 insertions, 199 deletions

diff --git a/src/execline/backtick.c b/src/execline/backtick.c
index fa7403f..9394456 100644
--- a/src/execline/backtick.c
+++ b/src/execline/backtick.c
@@ -12,22 +12,22 @@
 
 #include <execline/execline.h>
 
-#define USAGE "backtick [ -i | -I | -D default ] [ -N | -n ] var { prog... } remainder..."
+#define USAGE "backtick [ -i | -I | -D default ] [ -N | -n ] [ -E | -e ] var { prog... } remainder..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const **argv, char const *const *envp)
 {
   subgetopt_t localopt = SUBGETOPT_ZERO ;
-  pid_t pid ;
   int argc1, fdwstat ;
-  stralloc modif = STRALLOC_ZERO ;
-  size_t modifstart ;
-  int insist = 0, chomp = 1 ;
+  stralloc value = STRALLOC_ZERO ;
+  char const *var ;
+  char const *val ;
+  int insist = 0, chomp = 1, doimport = 0 ;
   char const *def = 0 ;
   PROG = "backtick" ;
   for (;;)
   {
-    int opt = subgetopt_r(argc, argv, "iINnD:", &localopt) ;
+    int opt = subgetopt_r(argc, argv, "iINnD:Ee", &localopt) ;
     if (opt < 0) break ;
     switch (opt)
     {
@@ -36,69 +36,51 @@ int main (int argc, char const **argv, char const *const *envp)
       case 'N' : chomp = 0 ; break ;
       case 'n' : chomp = 1 ; break ;
       case 'D' : def = localopt.arg ; break ;
+      case 'E' : doimport = 1 ; break ;
+      case 'e' : doimport = 0 ; break ;
       default : dieusage() ;
     }
   }
   argc -= localopt.ind ; argv += localopt.ind ;
 
   if (argc < 2) dieusage() ;
-  if (!*argv[0]) strerr_dief1x(100, "empty variable not accepted") ;
-  if (!stralloc_cats(&modif, argv[0]) || !stralloc_catb(&modif, "=", 1))
-    strerr_diefu1sys(111, "stralloc_catb") ;
-  modifstart = modif.len ;
-  argc-- ; argv++ ;
+  if (!argv[0][0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
+  argc-- ; var = *argv++ ;
   argc1 = el_semicolon(argv) ;
   if (!argc1) strerr_dief1x(100, "empty block") ;
   if (argc1 >= argc) strerr_dief1x(100, "unterminated block") ;
-
   argv[argc1] = 0 ;
-  pid = child_spawn1_pipe(argv[0], argv, envp, &fdwstat, 1) ;
-  if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
-  if (!slurp(&modif, fdwstat)) strerr_diefu1sys(111, "slurp") ;
-  close(fdwstat) ;
-  if (wait_pid(pid, &fdwstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
 
+  {
+    pid_t pid = child_spawn1_pipe(argv[0], argv, envp, &fdwstat, 1) ;
+    if (!pid) strerr_diefu2sys(111, "spawn ", argv[0]) ;
+    if (!slurp(&value, fdwstat) || !stralloc_0(&value))
+      strerr_diefu1sys(111, "slurp") ;
+    close(fdwstat) ;
+    if (wait_pid(pid, &fdwstat) < 0) strerr_diefu1sys(111, "wait_pid") ;
+  }
+
+  val = value.s ;
   if (wait_status(fdwstat))
   {
     if (insist >= 2)
       if (WIFSIGNALED(fdwstat)) strerr_dief1x(111, "child process crashed") ;
       else strerr_dief1x(WEXITSTATUS(fdwstat), "child process exited non-zero") ;
-    else if (insist)
-    {
-      modif.len = modifstart - 1 ;
-      chomp = 0 ;
-    }
-    else if (def)
-    {
-      modif.len = modifstart ;
-      if (!stralloc_cats(&modif, def)) strerr_diefu1sys(111, "stralloc_catb") ;
-    }
+    else if (insist) val = 0 ;
+    else if (def) val = def ;
   }
-  if (argc1 == argc - 1) return 0 ;
-  if (!stralloc_0(&modif)) strerr_diefu1sys(111, "stralloc_catb") ;
+  else if (strlen(value.s) < value.len - 1)
   {
-    size_t reallen = strlen(modif.s) ;
-    if (reallen < modif.len - 1)
+    if (insist >= 2)
+      strerr_dief1x(1, "child process output contained a null character") ;
+    else if (insist) val = 0 ;
+    else if (def)
     {
-      if (insist >= 2)
-        strerr_dief1x(1, "child process output contained a null character") ;
-      else if (insist)
-      {
-        modif.len = modifstart ;
-        modif.s[modif.len - 1] = 0 ;
-        chomp = 0 ;
-      }
-      else if (def)
-      {
-        modif.len = modifstart ;
-        if (!stralloc_catb(&modif, def, strlen(def)+1))
-          strerr_diefu1sys(111, "stralloc_catb") ;
-        strerr_warnw2x("child process output contained a null character", " - using default instead") ;
-      }
-      else modif.len = reallen + 1 ;
+      val = def ;
+      strerr_warnw2x("child process output contained a null character", " - using default instead") ;
     }
-    if (chomp && (modif.s[modif.len - 2] == '\n'))
-      modif.s[--modif.len - 1] = 0 ;
   }
-  xmexec_en(argv + argc1 + 1, envp, modif.s, modif.len, 1) ;
+  else if (chomp && (value.s[value.len - 2] == '\n'))
+    value.s[--value.len - 1] = 0 ;
+  el_modif_and_exec(argv + argc1 + 1, var, val, doimport) ;
 }
diff --git a/src/execline/deps-exe/getcwd b/src/execline/deps-exe/getcwd
index e7187fe..97021b5 100644
--- a/src/execline/deps-exe/getcwd
+++ b/src/execline/deps-exe/getcwd
@@ -1 +1,2 @@
+${LIBEXECLINE}
 -lskarnet
diff --git a/src/execline/deps-exe/getpid b/src/execline/deps-exe/getpid
index e7187fe..97021b5 100644
--- a/src/execline/deps-exe/getpid
+++ b/src/execline/deps-exe/getpid
@@ -1 +1,2 @@
+${LIBEXECLINE}
 -lskarnet
diff --git a/src/execline/deps-exe/withstdinas b/src/execline/deps-exe/withstdinas
index e7187fe..97021b5 100644
--- a/src/execline/deps-exe/withstdinas
+++ b/src/execline/deps-exe/withstdinas
@@ -1 +1,2 @@
+${LIBEXECLINE}
 -lskarnet
diff --git a/src/execline/forbacktickx.c b/src/execline/forbacktickx.c
index 1f3a0f1..2fc8bb8 100644
--- a/src/execline/forbacktickx.c
+++ b/src/execline/forbacktickx.c
@@ -12,20 +12,20 @@
 #include <execline/config.h>
 #include <execline/execline.h>
 
-#define USAGE "forbacktickx [ -p | -o okcode,okcode,... | -x breakcode,breakcode,... ] [ -N | -n ] [ -C | -c ] [ -0 | -d delim ] var { backtickcmd... } command..."
+#define USAGE "forbacktickx [ -p | -o okcode,okcode,... | -x breakcode,breakcode,... ] [ -E | -e ] [ -N | -n ] [ -C | -c ] [ -0 | -d delim ] var { backtickcmd... } command..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv)
 {
   char const *delim = "\n" ;
   char const *codes = 0 ;
-  int crunch = 0, chomp = 1, not = 1, par = 0 ;
+  int crunch = 0, chomp = 1, not = 1, par = 0, doimport = 0 ;
   PROG = "forbacktickx" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "pNnCc0d:o:x:", &l) ;
+      int opt = subgetopt_r(argc, argv, "pNnCc0d:o:x:Ee", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
@@ -54,6 +54,8 @@ int main (int argc, char const *const *argv)
           not = 1 ;
           break ;
         }
+        case 'E' : doimport = 1 ; break ;
+        case 'e' : doimport = 0 ; break ;
         default : dieusage() ;
       }
     }
@@ -65,7 +67,7 @@ int main (int argc, char const *const *argv)
   {
     unsigned int m = 0, i = 1 ;
     int fd = dup(0) ;
-    char const *newargv[argc + 18] ;
+    char const *newargv[argc + 19] ;
     char fmt[UINT_FMT] ;
     if (fd < 0)
     {
@@ -81,6 +83,7 @@ int main (int argc, char const *const *argv)
     newargv[m++] = EXECLINE_BINPREFIX "unexport" ;
     newargv[m++] = "!" ;
     newargv[m++] = EXECLINE_BINPREFIX "forstdin" ;
+    newargv[m++] = doimport ? "-E" : "-e" ;
     if (par) newargv[m++] = "-p" ;
     newargv[m++] = chomp ? "-n" : "-N" ;
     if (crunch) newargv[m++] = "-C" ;
diff --git a/src/execline/forstdin.c b/src/execline/forstdin.c
index 336aaa4..bacb1ae 100644
--- a/src/execline/forstdin.c
+++ b/src/execline/forstdin.c
@@ -9,16 +9,14 @@
 #include <skalibs/strerr2.h>
 #include <skalibs/stralloc.h>
 #include <skalibs/genalloc.h>
-#include <skalibs/env.h>
 #include <skalibs/sig.h>
 #include <skalibs/djbunix.h>
 #include <skalibs/skamisc.h>
 #include <skalibs/netstring.h>
 
-#include <execline/config.h>
 #include <execline/execline.h>
 
-#define USAGE "forstdin [ -p | -o okcode,okcode,... | -x breakcode,breakcode,... ] [ -N | -n ] [ -C | -c ] [ -0 | -d delim ] var command..."
+#define USAGE "forstdin [ -E | -e ] [ -p | -o okcode,okcode,... | -x breakcode,breakcode,... ] [ -N | -n ] [ -C | -c ] [ -0 | -d delim ] var command..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 static genalloc pids = GENALLOC_ZERO ; /* pid_t */
@@ -45,19 +43,20 @@ static void parallel_sigchld_handler (int sig)
   (void)sig ;
 }
 
-int main (int argc, char const **argv, char const *const *envp)
+int main (int argc, char const **argv)
 {
+  stralloc value = STRALLOC_ZERO ;
   char const *delim = "\n" ;
   size_t delimlen = 1 ;
   size_t nbc = 0 ;
   unsigned short okcodes[256] ;
-  int crunch = 0, chomp = 1, not = 1, eofcode = 1 ;
+  int crunch = 0, chomp = 1, not = 1, eofcode = 1, doimport = 0 ;
   PROG = "forstdin" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "pNnCc0d:o:x:", &l) ;
+      int opt = subgetopt_r(argc, argv, "pNnCc0d:o:x:Ee", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
@@ -81,81 +80,74 @@ int main (int argc, char const **argv, char const *const *envp)
           not = 1 ;
           if (!ushort_scanlist(okcodes, 256, l.arg, &nbc)) dieusage() ;
           break ;
+        case 'E' : doimport = 1 ; break ;
+        case 'e' : doimport = 0 ; break ;
         default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
   }
   if (argc < 2) dieusage() ;
+  if (!argv[0][0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
+
+  if (pids.s)
   {
-    stralloc modif = STRALLOC_ZERO ;
-    size_t envlen = env_len(envp) ;
-    size_t modifstart = strlen(argv[0]) + 1 ;
-    char const *newenv[envlen + 2] ;
-    if (!stralloc_ready(&modif, modifstart+1))
-      strerr_diefu1sys(111, "stralloc_ready") ;
-    memcpy(modif.s, argv[0], modifstart - 1) ;
-    modif.s[modifstart-1] = '=' ;
-    if (pids.s)
-    {
-      if (sig_catch(SIGCHLD, &parallel_sigchld_handler) < 0)
-        strerr_diefu1sys(111, "install SIGCHLD handler") ;
-    }
-    for (;;)
+    if (sig_catch(SIGCHLD, &parallel_sigchld_handler) < 0)
+      strerr_diefu1sys(111, "install SIGCHLD handler") ;
+  }
+  for (;;)
+  {
+    pid_t pid ;
+    value.len = 0 ;
+    if (delimlen)
     {
-      pid_t pid ;
-      modif.len = modifstart ;
-      if (delimlen)
-      {
-        int r = skagetlnsep(buffer_0, &modif, delim, delimlen) ;
-        if (!r) break ;
-        else if (r < 0)
-        {
-          if (errno != EPIPE) strerr_diefu1sys(111, "skagetlnsep") ;
-          if (chomp) break ;
-        }
-        if (crunch && modif.len == modifstart + 1) continue ;
-        if (chomp) modif.len-- ;
-      }
-      else
+      int r = skagetlnsep(buffer_0, &value, delim, delimlen) ;
+      if (!r) break ;
+      else if (r < 0)
       {
-        size_t unread = 0 ;
-        if (netstring_get(buffer_0, &modif, &unread) <= 0)
-        {
-          if (netstring_okeof(buffer_0, unread)) break ;
-          else strerr_diefu1sys(111, "netstring_get") ;
-        }
-      }
-      eofcode = 0 ;
-      if (!stralloc_0(&modif)) strerr_diefu1sys(111, "stralloc_0") ;
-      if (!env_mergen(newenv, envlen+2, envp, envlen, modif.s, modif.len, 1))
-        strerr_diefu1sys(111, "merge environment") ;
-      if (pids.s) sig_block(SIGCHLD) ;
-      pid = el_spawn0(argv[1], argv + 1, newenv) ;
-      if (!pid) strerr_diefu2sys(111, "spawn ", argv[1]) ;
-      if (pids.s)
-      {
-        if (!genalloc_append(pid_t, &pids, &pid))
-          strerr_diefu1sys(111, "genalloc_append") ;
-        sig_unblock(SIGCHLD) ;
+        if (errno != EPIPE) strerr_diefu1sys(111, "skagetlnsep") ;
+        if (chomp) break ;
       }
-      else
+      if (crunch && value.len == 1) continue ;
+      if (chomp) value.len-- ;
+    }
+    else
+    {
+      size_t unread = 0 ;
+      if (netstring_get(buffer_0, &value, &unread) <= 0)
       {
-        int wstat ;
-        if (wait_pid(pid, &wstat) < 0)
-          strerr_diefu2sys(111, "wait for ", argv[1]) ;
-        if (not == isok(okcodes, nbc, wait_estatus(wstat)))
-          return wait_estatus(wstat) ;
+        if (netstring_okeof(buffer_0, unread)) break ;
+        else strerr_diefu1sys(111, "netstring_get") ;
       }
     }
-    stralloc_free(&modif) ;
+    eofcode = 0 ;
+    if (!stralloc_0(&value)) strerr_diefu1sys(111, "stralloc_0") ;
+    if (pids.s) sig_block(SIGCHLD) ;
+    pid = el_modif_and_spawn(argv + 1, argv[0], value.s, doimport) ;
+    if (!pid) strerr_diefu2sys(111, "spawn ", argv[1]) ;
+    if (pids.s)
+    {
+      if (!genalloc_append(pid_t, &pids, &pid))
+        strerr_diefu1sys(111, "genalloc_append") ;
+      sig_unblock(SIGCHLD) ;
+    }
+    else
+    {
+      int wstat ;
+      if (wait_pid(pid, &wstat) < 0)
+        strerr_diefu2sys(111, "wait for ", argv[1]) ;
+      if (not == isok(okcodes, nbc, wait_estatus(wstat)))
+        return wait_estatus(wstat) ;
+    }
   }
   if (pids.s)
+  {
     for (;;)
     {
       sig_block(SIGCHLD) ;
       if (!pids.len) break ;
       sig_pause() ;
     }
+  }
   return eofcode ;
 }
diff --git a/src/execline/forx.c b/src/execline/forx.c
index be03794..8e6659b 100644
--- a/src/execline/forx.c
+++ b/src/execline/forx.c
@@ -13,7 +13,7 @@
 #include <execline/config.h>
 #include <execline/execline.h>
 
-#define USAGE "forx [ -p ] [ -o okcode,okcode,... | -x breakcode,breakcode,... ] var { values... } command..."
+#define USAGE "forx [ -E | -e ] [ -p ] [ -o okcode,okcode,... | -x breakcode,breakcode,... ] var { values... } command..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 static int isok (unsigned short const *tab, unsigned int n, int code)
@@ -42,19 +42,19 @@ static int waitn_code (unsigned short const *tab, unsigned int nbc, pid_t *pids,
   return ok ;
 }
 
-int main (int argc, char const **argv, char const *const *envp)
+int main (int argc, char const **argv)
 {
-  char const *x ;
-  int argc1 ;
+  char const *var ;
   unsigned short okcodes[256] ;
   size_t nbc = 0 ;
-  int flagpar = 0, not = 1 ;
+  int flagpar = 0, not = 1, doimport = 0 ;
+  unsigned int argc1 ;
   PROG = "forx" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "po:x:", &l) ;
+      int opt = subgetopt_r(argc, argv, "po:x:Ee", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
@@ -67,6 +67,8 @@ int main (int argc, char const **argv, char const *const *envp)
           not = 1 ;
           if (!ushort_scanlist(okcodes, 256, l.arg, &nbc)) dieusage() ;
           break ;
+        case 'E' : doimport = 1 ; break ;
+        case 'e' : doimport = 0 ; break ;
         default : dieusage() ;
       }
     }
@@ -74,32 +76,17 @@ int main (int argc, char const **argv, char const *const *envp)
   }
 
   if (argc < 2) dieusage() ;
-  x = argv[0] ; if (!*x) dieusage() ;
-  if (x[0] == EXECLINE_BLOCK_QUOTE_CHAR)
-    strerr_warnw3x("variable ", x, " starts with a block quoting character") ;
-  argv++ ; argc-- ;
+  if (!argv[0][0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
+  var = *argv++ ; argc-- ;
   argc1 = el_semicolon(argv) ;
   if (argc1 >= argc) strerr_dief1x(100, "unterminated block") ;
   if (!argc1 || (argc1 + 1 == argc)) return 0 ;
+
   {
-    size_t envlen = env_len(envp) ;
-    size_t varlen = strlen(x) ;
-    unsigned int i = 0 ;
     pid_t pids[flagpar ? argc1 : 1] ;
-    char const *newenv[envlen + 2] ;
-
-    for (; i < (unsigned int)argc1 ; i++)
+    for (unsigned int i = 0 ; i < argc1 ; i++)
     {
-      pid_t pid ;
-      size_t vallen = strlen(argv[i]) ;
-      char modif[varlen + vallen + 2] ;
-      memcpy(modif, x, varlen) ;
-      modif[varlen] = '=' ;
-      memcpy(modif + varlen + 1, argv[i], vallen) ;
-      modif[varlen + vallen + 1] = 0 ;
-      if (!env_mergen(newenv, envlen + 2, envp, envlen, modif, varlen + vallen + 2, 1))
-        strerr_diefu1sys(111, "build new environment") ;
-      pid = el_spawn0(argv[argc1+1], argv + argc1 + 1, newenv) ;
+      pid_t pid = el_modif_and_spawn(argv + argc1 + 1, var, argv[i], doimport) ;
       if (!pid) strerr_diefu2sys(111, "spawn ", argv[argc1+1]) ;
       if (flagpar) pids[i] = pid ;
       else
diff --git a/src/execline/getcwd.c b/src/execline/getcwd.c
index d41bd5a..2a82924 100644
--- a/src/execline/getcwd.c
+++ b/src/execline/getcwd.c
@@ -2,23 +2,39 @@
 
 #include <string.h>
 
+#include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
 #include <skalibs/stralloc.h>
 #include <skalibs/djbunix.h>
-#include <skalibs/exec.h>
 
-#define USAGE "getcwd variable prog..."
+#include <execline/execline.h>
+
+#define USAGE "getcwd [ -E | -e ] variable prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv)
 {
+  int doimport = 0 ;
   stralloc sa = STRALLOC_ZERO ;
   PROG = "getcwd" ;
-  if (argc < 3) strerr_dieusage(100, USAGE) ;
-  if (strchr(argv[1], '='))
-    strerr_dief2x(100, "invalid variable name: ", argv[1]) ;
-  if (!stralloc_cats(&sa, argv[1]) || !stralloc_catb(&sa, "=", 1))
-    strerr_diefu1sys(111, "stralloc_catb") ;
-  if (sagetcwd(&sa) < 0) strerr_diefu1sys(111, "getcwd") ;
-  if (!stralloc_0(&sa)) strerr_diefu1sys(111, "stralloc_catb") ;
-  xmexec_n(argv + 2, sa.s, sa.len, 1) ;
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "Ee", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'E' : doimport = 1 ; break ;
+        case 'e' : doimport = 0 ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+  if (argc < 2) dieusage() ;
+  if (!argv[0][0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
+
+  if (sagetcwd(&sa) < 0 || !stralloc_0(&sa)) strerr_diefu1sys(111, "getcwd") ;
+  el_modif_and_exec(argv + 1, argv[0], sa.s, doimport) ;
 }
diff --git a/src/execline/getpid.c b/src/execline/getpid.c
index 06c4aaf..64866de 100644
--- a/src/execline/getpid.c
+++ b/src/execline/getpid.c
@@ -4,25 +4,37 @@
 #include <unistd.h>
 
 #include <skalibs/types.h>
+#include <skalibs/sgetopt.h>
 #include <skalibs/strerr2.h>
-#include <skalibs/exec.h>
 
-#define USAGE "getpid variable prog..."
+#include <execline/execline.h>
+
+#define USAGE "getpid [ -E | -e ] variable prog..."
+#define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv)
 {
-  size_t len ;
+  int doimport = 0 ;
+  char fmt[PID_FMT] ;
   PROG = "getpid" ;
-  if (argc < 3) strerr_dieusage(100, USAGE) ;
-  len = strlen(argv[1]) ;
-  if (memchr(argv[1], '=', len))
-    strerr_dief2x(100, "invalid variable name: ", argv[1]) ;
   {
-    size_t i = len+1 ;
-    char fmt[PID_FMT + len + 2] ;
-    memcpy(fmt, argv[1], len) ;
-    fmt[len] = '=' ;
-    i += pid_fmt(fmt+i, getpid()) ; fmt[i++] = 0 ;
-    xmexec_n(argv+2, fmt, i, 1) ;
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "Ee", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'E' : doimport = 1 ; break ;
+        case 'e' : doimport = 0 ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
   }
+  if (argc < 2) dieusage() ;
+  if (!argv[0][0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
+
+  fmt[pid_fmt(fmt, getpid())] = 0 ;
+  el_modif_and_exec(argv + 1, argv[0], fmt, doimport) ;
 }
diff --git a/src/execline/withstdinas.c b/src/execline/withstdinas.c
index 467b68b..cd025bf 100644
--- a/src/execline/withstdinas.c
+++ b/src/execline/withstdinas.c
@@ -6,22 +6,23 @@
 #include <skalibs/strerr2.h>
 #include <skalibs/stralloc.h>
 #include <skalibs/djbunix.h>
-#include <skalibs/exec.h>
 
-#define USAGE "withstdinas [ -i | -I | -D default ] [ -N | -n ] var remainder..."
+#include <execline/execline.h>
+
+#define USAGE "withstdinas [ -i | -I | -D default ] [ -N | -n ] [ -E | -e ] var remainder..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
-int main (int argc, char const **argv)
+int main (int argc, char const *const *argv)
 {
   subgetopt_t localopt = SUBGETOPT_ZERO ;
-  stralloc modif = STRALLOC_ZERO ;
-  size_t modifstart ;
-  int insist = 0, chomp = 1 ;
+  stralloc value = STRALLOC_ZERO ;
+  int insist = 0, chomp = 1, doimport = 0 ;
   char const *def = 0 ;
+  char const *val ;
   PROG = "withstdinas" ;
   for (;;)
   {
-    int opt = subgetopt_r(argc, argv, "iINnD:", &localopt) ;
+    int opt = subgetopt_r(argc, argv, "iINnD:Ee", &localopt) ;
     if (opt < 0) break ;
     switch (opt)
     {
@@ -30,41 +31,29 @@ int main (int argc, char const **argv)
       case 'N' : chomp = 0 ; break ;
       case 'n' : chomp = 1 ; break ;
       case 'D' : def = localopt.arg ; break ;
+      case 'E' : doimport = 1 ; break ;
+      case 'e' : doimport = 0 ; break ;
       default : dieusage() ;
     }
   }
   argc -= localopt.ind ; argv += localopt.ind ;
-
   if (!argc) dieusage() ;
-  if (!*argv[0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
-  if (!stralloc_cats(&modif, argv[0]) || !stralloc_catb(&modif, "=", 1))
-    strerr_diefu1sys(111, "stralloc_catb") ;
-  modifstart = modif.len ;
-  if (!slurp(&modif, 0)) strerr_diefu1sys(111, "slurp") ;
-  if (!stralloc_0(&modif)) strerr_diefu1sys(111, "stralloc_catb") ;
+  if (!argv[0][0] || strchr(argv[0], '=')) strerr_dief1x(100, "invalid variable name") ;
+
+  if (!slurp(&value, 0) || !stralloc_0(&value)) strerr_diefu1sys(111, "slurp") ;
+  val = value.s ;
+  if (strlen(value.s) < value.len - 1)
   {
-    size_t reallen = strlen(modif.s) ;
-    if (reallen < modif.len - 1)
+    if (insist >= 2)
+      strerr_dief1x(1, "stdin contained a null character") ;
+    else if (insist) val = 0 ;
+    else if (def)
     {
-      if (insist >= 2)
-        strerr_dief1x(1, "stdin contained a null character") ;
-      else if (insist)
-      {
-        modif.len = modifstart ;
-        modif.s[modif.len - 1] = 0 ;
-        chomp = 0 ;
-      }
-      else if (def)
-      {
-        modif.len = modifstart ;
-        if (!stralloc_catb(&modif, def, strlen(def)+1))
-          strerr_diefu1sys(111, "stralloc_catb") ;
-        strerr_warnw2x("stdin contained a null character", " - using default instead") ;
-      }
-      else modif.len = reallen + 1 ;
+      val = def ;
+      strerr_warnw2x("stdin contained a null character", " - using default instead") ;
     }
-    if (chomp && (modif.s[modif.len - 2] == '\n'))
-      modif.s[--modif.len - 1] = 0 ;
   }
-  xmexec0_n(argv + 1, modif.s, modif.len, 1) ;
+  else if (chomp && (value.s[value.len - 2] == '\n'))
+    value.s[--value.len - 1] = 0 ;
+  el_modif_and_exec(argv + 1, argv[0], val, doimport) ;
 }
diff --git a/src/include/execline/execline.h b/src/include/execline/execline.h
index bbe4db9..144283d 100644
--- a/src/include/execline/execline.h
+++ b/src/include/execline/execline.h
@@ -4,6 +4,7 @@
 #define EXECLINE_H
 
 #include <sys/types.h>
+
 #include <skalibs/gccattributes.h>
 #include <skalibs/buffer.h>
 #include <skalibs/stralloc.h>
@@ -76,4 +77,10 @@ struct elsubst_s
 
 extern int el_substitute (stralloc *, char const *, size_t, char const *, char const *, elsubst_t const *, unsigned int) ;
 
+
+/* Execution with or without substitution */
+
+extern void el_modif_and_exec (char const *const *, char const *, char const *, int) gccattr_noreturn ;
+extern pid_t el_modif_and_spawn (char const *const *, char const *, char const *, int) ;
+
 #endif
diff --git a/src/libexecline/deps-lib/execline b/src/libexecline/deps-lib/execline
index 96d4e18..e896f2f 100644
--- a/src/libexecline/deps-lib/execline
+++ b/src/libexecline/deps-lib/execline
@@ -1,5 +1,7 @@
 el_execsequence.o
 el_getstrict.o
+el_modif_and_exec.o
+el_modif_and_spawn.o
 el_parse.o
 el_parse_from_buffer.o
 el_parse_from_string.o
diff --git a/src/libexecline/el_modif_and_exec.c b/src/libexecline/el_modif_and_exec.c
new file mode 100644
index 0000000..e2a3618
--- /dev/null
+++ b/src/libexecline/el_modif_and_exec.c
@@ -0,0 +1,36 @@
+/* ISC license. */
+
+#include <string.h>
+
+#include <skalibs/env.h>
+#include <skalibs/exec.h>
+
+#include <execline/config.h>
+#include <execline/execline.h>
+
+void el_modif_and_exec (char const *const *argv, char const *var, char const *value, int doimport)
+{
+  size_t varlen = strlen(var) ;
+  size_t modiflen = value ? varlen + strlen(value) + 2 : 1 ;
+  char modifs[modiflen] ;
+  if (value)
+  {
+    memcpy(modifs, var, varlen) ;
+    modifs[varlen] = '=' ;
+    memcpy(modifs + varlen + 1, value, modiflen - varlen - 1) ;
+  }
+  if (doimport)
+  {
+    size_t m = 0 ;
+    char const *newargv[env_len(argv) + 6] ;
+    newargv[m++] = EXECLINE_BINPREFIX "importas" ;
+    newargv[m++] = "-ui" ;
+    newargv[m++] = "--" ;
+    newargv[m++] = var ;
+    newargv[m++] = var ;
+    while (*argv) newargv[m++] = *argv++ ;
+    newargv[m++] = 0 ;
+    xmexec0_n(newargv, value ? modifs : var, value ? modiflen : varlen + 1, 1) ;
+  }
+  else xmexec0_n(argv, value ? modifs : var, value ? modiflen : varlen + 1, 1) ;
+}
diff --git a/src/libexecline/el_modif_and_spawn.c b/src/libexecline/el_modif_and_spawn.c
new file mode 100644
index 0000000..0070052
--- /dev/null
+++ b/src/libexecline/el_modif_and_spawn.c
@@ -0,0 +1,39 @@
+/* ISC license. */
+
+#include <string.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/env.h>
+
+#include <execline/config.h>
+#include <execline/execline.h>
+
+pid_t el_modif_and_spawn (char const *const *argv, char const *var, char const *value, int doimport)
+{
+  size_t varlen = strlen(var) ;
+  size_t modiflen = value ? varlen + strlen(value) + 2 : 1 ;
+  size_t envlen = env_len((char const *const *)environ) ;
+  char const *newenv[envlen + 2] ;
+  char modifs[modiflen] ;
+  if (value)
+  {
+    memcpy(modifs, var, varlen) ;
+    modifs[varlen] = '=' ;
+    memcpy(modifs + varlen + 1, value, modiflen - varlen - 1) ;
+  }
+  if (!env_mergen(newenv, envlen + 2, (char const *const *)environ, envlen, value ? modifs : var, value ? modiflen : varlen + 1, 1)) return 0 ;
+  if (doimport)
+  {
+    size_t m = 0 ;
+    char const *newargv[env_len(argv) + 6] ;
+    newargv[m++] = EXECLINE_BINPREFIX "importas" ;
+    newargv[m++] = "-ui" ;
+    newargv[m++] = "--" ;
+    newargv[m++] = var ;
+    newargv[m++] = var ;
+    while (*argv) newargv[m++] = *argv++ ;
+    newargv[m++] = 0 ;
+    return el_spawn0(newargv[0], newargv, newenv) ;
+  }
+  else return el_spawn0(argv[0], argv, newenv) ;
+}
diff --git a/src/libexecline/el_spawn0.c b/src/libexecline/el_spawn0.c
index 7e10902..0cfe017 100644
--- a/src/libexecline/el_spawn0.c
+++ b/src/libexecline/el_spawn0.c
@@ -1,6 +1,7 @@
 /* ISC license. */
 
 #include <skalibs/djbunix.h>
+
 #include <execline/config.h>
 #include <execline/execline.h>