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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-18 20:03:23 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-18 20:03:23 +0000 |
| commit | f316a2ed52195135a35e32d7096e876357c48c69 (patch) | |
| tree | 5f4486b9a5a213a69e66ef574d6bc643a207981c /doc/tryexec.html | |
| download | execline-f316a2ed52195135a35e32d7096e876357c48c69.tar.xz | |
initial commit: rc for execline-2.0.0.0
Diffstat (limited to 'doc/tryexec.html')
| -rw-r--r-- | doc/tryexec.html | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/doc/tryexec.html b/doc/tryexec.html new file mode 100644 index 0000000..2fcc7b6 --- /dev/null +++ b/doc/tryexec.html @@ -0,0 +1,67 @@ +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>execline: the tryexec command</title> + <meta name="Description" content="execline: the tryexec command" /> + <meta name="Keywords" content="execline command tryexec" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">execline</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">skarnet.org</a> +</p> + +<h1> The <tt>tryexec</tt> program </h1> + +<p> +<tt>tryexec</tt> executes into a command line, with a fallback. +</p> + +<h2> Interface </h2> + +<p> + In an <a href="execlineb.html">execlineb</a> script: +</p> + +<pre> + tryexec [ -n ] [ -c ] [ -l ] [ -a argv0 ] { <em>prog1...</em> } <em>prog2...</em> +</pre> + +<ul> + <li> <tt>tryexec</tt> reads <em>prog1...</em> in a +<a href="el_semicolon.html">block</a>. It then executes into it, +completely forgetting <em>prog2...</em> </li> + <li> If for some reason the <tt>execve()</tt> fails - for instance, +a non-executable <em>prog1</em> - then <tt>tryexec</tt> executes +into <em>prog2...</em> instead. </li> +</ul> + +<h2> Options </h2> + +<ul> + <li> <tt>-n</tt> : reverse <em>prog1...</em> and <em>prog2...</em>'s +role. The latter becomes the main execution path and the former becomes +the fallback. </li> +</ul> + +<p> + The <tt>-c</tt>, <tt>-l</tt> and <tt>-a</tt> options have the same +semantics as with the <a href="exec.html">exec</a> program. +</p> + +<h2> Notes </h2> + +<ul> + <li> <tt>tryexec <em>prog1...</em> "" <em>prog2...</em></tt> would be +equivalent to +<tt>sh -c 'exec <em>prog1...</em> || exec <em>prog2...</em>'</tt>, if +such a shell construct existed. Unfortunately, the shell language does +not offer that functionality. </li> +</ul> + +</body> +</html> |