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diff --git a/doc/cd.html b/doc/cd.html new file mode 100644 index 0000000..fbd6687 --- /dev/null +++ b/doc/cd.html @@ -0,0 +1,60 @@ +<html> + <head> + <meta name="viewport" content="width=device-width, initial-scale=1.0" /> + <meta name="color-scheme" content="dark light" /> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>execline: the cd command</title> + <meta name="Description" content="execline: the cd command" /> + <meta name="Keywords" content="execline command cd chdir cd" /> + <!-- <link rel="stylesheet" type="text/css" href="//skarnet.org/default.css" /> --> +</head> +<body> + +<p> +<a href="index.html">execline</a><br /> +<a href="//skarnet.org/software/">Software</a><br /> +<a href="//skarnet.org/">skarnet.org</a> +</p> + +<h1> The <tt>cd</tt> program </h1> + +<p> +<tt>cd</tt> changes the current working directory to a +given directory, then executes a program. +</p> + +<h2> Interface </h2> + +<pre> + cd <em>dir</em> <em>prog...</em> +</pre> + +<p> +<tt>cd</tt> performs a +<a href="https://pubs.opengroup.org/onlinepubs/9799919799/functions/chdir.html">chdir()</a> +system call on <em>dir</em>, then execs into <em>prog...</em>. +</p> + +<h2> Notes </h2> + +<ul> + <li> This <tt>cd</tt> program will never be invoked by a shell, unless its full path +is explicitly given to the shell command line. So it is perfectly acceptable and valid +to have a <tt>cd</tt> binary in the filesystem. No confusion will be possible: shells +will invoke their builtin +<a href="https://pubs.opengroup.org/onlinepubs/9799919799/utilities/cd.html">cd</a> +utility, and execline scripts will invoke the <tt>cd</tt> binary. </li> + <li> Previous versions of POSIX also required a conformant <tt>cd</tt> binary to exist +in the filesystem, for no reason at all. So, in previous execline versions, +a <tt>posix-cd</tt> binary was present, and <tt>cd</tt> could be installed as a symlink +to it when execline was configured with the <tt>--enable-pedantic-posix</tt> option. +This allowed distributions to make execline binaries, including <tt>cd</tt>, available +in PATH, while strictly conforming to POSIX. This requirement has now been relaxed by +POSIX, so the needlessly complex <tt>posix-cd</tt> program was replaced with this +simpler <tt>cd</tt>, that can now be made available in PATH without breaking strict +conformance. </li> +</ul> + +</body> +</html> |