Differences between revisions 2 and 3
Revision 2 as of 2009-02-10 15:05:49
Size: 795
Editor: GreyCat
Comment: POSIX too
Revision 3 as of 2009-02-10 15:55:01
Size: 799
Editor: NeilMoore
Comment: don't use [ -a ], since Posix leaves the behaviour of test unspecified when there are more than four arguments
Deletions are marked like this. Additions are marked like this.
Line 18: Line 18:
if [ -L "$symlink" -a ! -e "$symlink" ]; then if [ -L "$symlink" ] && [ ! -e "$symlink" ]; then

The documentation on this is fuzzy, but it turns out you can do this with shell builtins:

# Bash
if [[ -L $symlink && ! -e $symlink ]]; then
  echo "$symlink is dangling"
fi

The -e test (like all other tests besides -L or -h) follows the symbolic link, and therefore it checks on the thing pointed to, not on the link itself. The -L test does not follow the symlink, so it's checking on the link itself. Together, they can indicate the presence of a dangling symlink.

POSIX has these same tests, with the same semantics, so it can also be done with the [ command:

# POSIX
if [ -L "$symlink" ] && [ ! -e "$symlink" ]; then
  echo "$symlink is dangling"
fi

BashFAQ/097 (last edited 2016-10-29 17:13:52 by jaffer)