bash/fish command to print absolute path to a file

Question

Question: is there a simple sh/bash/zsh/fish/... command to print the absolute path of whichever file I feed it?

Usage case: I'm in directory /a/b and I'd like to print the full path to file c on the command-line so that I can easily paste it into another program: /a/b/c. Simple, yet a little program to do this could probably save me 5 or so seconds when it comes to handling long paths, which in the end adds up. So it surprises me that I can't find a standard utility to do this — is there really none?

Here's a sample implementation, abspath.py:

#!/usr/bin/python
# Author: Diggory Hardy <[email protected]>
# Licence: public domain
# Purpose: print the absolute path of all input paths

import sys
import os.path
if len(sys.argv)>1:
    for i in range(1,len(sys.argv)):
        print os.path.abspath( sys.argv[i] )
    sys.exit(0)
else:
    print >> sys.stderr, "Usage: ",sys.argv[0]," PATH."
    sys.exit(1)

Answer 1

Try realpath.

~ $ realpath .bashrc
/home/username/.bashrc

Answer 2

#! /bin/sh
echo `cd \`dirname $1\`; pwd`/`basename $1`

Answer 3

Try readlink which will resolve symbolic links:

readlink -e /foo/bar/baz

Answer 4

If you don't have readlink or realpath utilities than you can use following function which works in bash and zsh (not sure about the rest).

abspath () { case "$1" in /*)printf "%s\n" "$1";; *)printf "%s\n" "$PWD/$1";; esac; }

This also works for nonexistent files (as does the python function os.path.abspath).

Unfortunately abspath ./../somefile doesn't get rid of the dots.