Find only destination of symlink

For use in a shell-script, I’m looking for a commandline-way to get the destination of a symbolic link. The closest I’ve come so far is stat -N src, which outputs src -> dst. Of course I could parse the output and get dst, but I wonder if there is some direct way of getting the destination.

Answers:

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Method 1

Another option would be to use the specifically designed command readlink if available.

E.g.

$ readlink -f `command -v php`
/usr/bin/php7.1

Method 2

On Mac OS X and FreeBSD/NetBSD/etc. it’s:

stat -f %Y <filename>

More generically I guess the solution is (stat –printf=%N uses weird quotes):

ls -l b | sed -e 's/.* -> //'

Example:

# ln -s a b
# stat -f %Y b
a

Another method is:

# find b -maxdepth 0 -printf %l
a#

The last line is mangled because it has no newline, but that is fine if you need the result in a variable, like so

# f=$(find b -maxdepth 0 -printf %l)
# echo $f
a

The -maxdepth is needed to prevent find from descending into directories if b happens to be a directory.

Method 3

This can be done using GNU find: find src -prune -printf "%ln".

Method 4

realpath command of coreutils package,

as linked in readlink command’s manual page.

for example:

realpath /bin/python

outputs

/usr/bin/python2.7

on my machine.

Method 5

On a system where I have no readlink or stat commands but I do have Python 2.x, I’m using a short script:

#!/usr/bin/env python

import os, sys

if __name__ == "__main__":
    src = sys.argv[1]
    target = os.readlink(src)
    if not os.path.isabs(target):
            target = os.path.abspath(os.path.join(os.path.dirname(src), target))
    print target

Note that unlike readlink -f this may only follow one level of symlink.

Method 6

Portable pure Bash realpath

bash_realpath() {
  # print the resolved path
  # @params
  # 1: the path to resolve
  # @return
  # &1: the resolved link path

  local path="${1}"
  while [[ -L ${path} && "$(ls -l "${path}")" =~ -> (.*) ]]
  do
    path="${BASH_REMATCH[1]}"
  done
  echo "${path}"
}

Method 7

Portably: no luck except using heuristics to parse ls -l output, or use perl -le 'print readlink("some-file")'

some systems have a readlink command, some with a -f option to obtain the absolute path.

There are various implementations of a stat command as a wrapper for the stat/lstat system calls. The GNU one is not useful in that regard, but zsh’s builtin one is more so:

zmodload zsh/stat
stat +link the-link

Still with zsh, you can get the absolute path of a file (removes every symlink component) with the :A modifier (applies to variable expansion, history expansion and globbing:

~$ gstat -c %N b
`b' -> `a'
~$ var=b
~$ echo $var:A
/home/me/a
~$ echo b(:A)
/home/me/a
~$ echo ?(@:A)
/home/me/a

Method 8

Added a pure sh version, hoping it to be more portable if bash is not installed :

$ cat ./realpath.sh
#!/usr/bin/env sh

bash_realpath() {
  # print the resolved path
  # @params
  # 1: the path to resolve
  # @return
  # &1: the resolved link path

  for path;do
    while [ -L "${path}" ]
    do
      path="$(ls -l "${path}" | awk '{print $NF}')"
    done
    which "${path}"
  done
}

bash_realpath "[email protected]"

Use case :

$ ./realpath.sh $(which gcc python)
/usr/bin/x86_64-linux-gnu-gcc-6
/usr/bin/python2.7

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