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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2017-04-21 09:13:00 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2017-04-21 09:13:00 +0000 |
| commit | cb49cb30fe65d4ee317572f232f7017a8c1fe6a2 (patch) | |
| tree | e6b55eb3a44ee3e9c4a9c22961f46572725a5c13 /doc | |
| parent | 5ba9d6993063e2398e5763736ba50e0f037abe3e (diff) | |
| download | s6-portable-utils-cb49cb30fe65d4ee317572f232f7017a8c1fe6a2.tar.gz s6-portable-utils-cb49cb30fe65d4ee317572f232f7017a8c1fe6a2.tar.xz s6-portable-utils-cb49cb30fe65d4ee317572f232f7017a8c1fe6a2.zip | |
Add -n to s6-ln; document its nonposixness
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/s6-ln.html | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/doc/s6-ln.html b/doc/s6-ln.html index 3ca0245..1417c35 100644 --- a/doc/s6-ln.html +++ b/doc/s6-ln.html @@ -25,7 +25,7 @@ <h2> Interface </h2> <pre> - s6-ln [ -s ] [ -f ] [ -L ] [ -P ] <em>old</em> <em>new</em> + s6-ln [ -n ] [ -s ] [ -f ] [ -L ] [ -P ] <em>source...</em> <em>target</em> </pre> <p> @@ -33,12 +33,31 @@ <a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ln.html">ln</a> utility. </p> +<h2> Options </h2> + +<ul> + <li> <tt>-s</tt> : create a symbolic link instead of a hard link </li> + <li> <tt>-f</tt> : force replacement of an existing <em>target</em> </li> + <li> <tt>-L</tt> : link targets of symlinks in <em>source...</em> </li> + <li> <tt>-P</tt> : link symlinks in <em>source...</em> themselves </li> + <li> <tt>-n</tt> : if <em>target</em> is a symlink to a directory, replace +it instead of adding a link in the directory </li> +</ul> + <h2> Posixness </h2> <p> - s6-ln <strong>is</strong> suitable as a Single Unix + s6-ln <strong>would be</strong> suitable as a Single Unix <a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ln.html">ln</a> -program. +program, except that POSIX mandates that a preexisting <em>target</em> must first +be <tt>unlink()</tt>ed and then (<tt>sym</tt>)<tt>link()</tt>ed, which prevents +atomic replacements. + <tt>s6-ln</tt> aims to be reliable and allow for atomic replacements, so it +deviates from POSIX on that point: when <em>target</em> exists and needs to +be replaced, <tt>s6-ln</tt> first creates a (sym)link to a unique temporary +name, then <tt>rename()</tt>s the temporary name to <em>target</em>. This +behaviour makes sure that <em>target</em> is atomically replaced - there's +no point in time where it does not exist. </p> </body> |