How can I derefence symbolic links in bash?

user_67829 0
Viewed 34212

How can I take any given path in bash and convert it to it's canonical form, dereferencing any symbolic links that may be contained within the path?

For example:

~$ mkdir /tmp/symtest
~$ cd /tmp/symtest/
/tmp/symtest$ mkdir -p foo/bar cat/dog
/tmp/symtest$ cd foo/bar/
/tmp/symtest/foo/bar$ ln -s ../../cat cat
/tmp/symtest/foo/bat$ cd ../../
/tmp/symtest$ tree
.
|-- cat
|   `-- dog
`-- foo
    `-- bar
       `-- cat -> ../../cat

6 directories, 0 files

How can I get the full canonical path of /tmp/symtest/foo/bar/cat (i.e: /tmp/symtest/cat)?

symlink bash
2 Answers

Thanks to Andy Skelton, it appears the answer is readlink -f:

$:/tmp/symtest$ readlink -f /tmp/symtest/foo/bar/cat
/tmp/symtest/cat
user_678290

Here's a function that will resolve symbolic links
It's original purpose is to resolve the full path to the calling script pointed to by a /usr/bin symlink

# resolve symbolic links
function resolve_link() {
  local LINK_FILE=${1:-${BASH_SOURCE[0]}}
  local FILE_TYPE=`file $LINK_FILE | awk '{print $2}'`
  local LINK_TO=$LINK_FILE
  while [ $FILE_TYPE = "symbolic" ]; do
    LINK_TO=`readlink $LINK_FILE`
    FILE_TYPE=`file $LINK_TO | awk '{print $2}'`
  done
  echo $LINK_TO
}

BASH_SOURCE_RESOLVED=$(resolve_link)
echo $BASH_SOURCE_RESOLVED

It doesn't use recursion but then again I've never used recursion in bash

user_5667410
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