How to get script file path inside script itself when called through sym link - linux

When I need to get path to the script file inside script itself I use something like this:
`dirname $0`
that works file until I call the script through sym link to it. In that case above code prints the location of the link instead the original file.
Is there a way to get the path of the original script file, not the link?
Thanks,
Mike

if [ -L $0 ] ; then
DIR=$(dirname $(readlink -f $0)) ;
else
DIR=$(dirname $0) ;
fi ;

You really need to read the following BashFAQ article:
BashFAQ/028 - How do I determine the location of my script? I want to read some config files from the same place.
The truth is, the $0 hacks are NOT reliable, and they will fail whenever applications are started with a zeroth argument that is not the application's path. For example, login(1) will put a - in front of your application name in $0, causing breakage, and whenever you invoke an application that's in PATH $0 won't contain the path to your application but just the filename, which means you can't extract any location information out of it. There are a LOT more ways in which this can fail.
Bottom line: Don't rely on the hack, the truth is you cannot figure out where your script is, so use a configuration option to set the directory of your config files or whatever you need the script's path for.

Use readlink for that:
readlink -f "$0"

Dir=$(dirname $(readlink -f "$0"))

I suggest this one:
dirname $(realpath $0)
example:
skaerst#test01-centos7:~/Documents> ../test/path.sh
dirname realpath: /home/skaerst/test
skaerst#test01-centos7:~/Documents> cat ../test/path.sh
#!/bin/bash
echo "dirname realpath: $(dirname $(realpath $0))"
works with symlinks too because realpath uses -P by default:
skaerst#test01-centos7:~/Documents> ln -s ../test/path.sh p
skaerst#test01-centos7:~/Documents> ./p
dirname realpath: /home/skaerst/test
realpath is available with coreutils >8.5, I guess
skaerst#test01-centos7:~/Documents> rpm -qf $(which realpath) $(which dirname)
coreutils-8.22-15.el7_2.1.x86_64
coreutils-8.22-15.el7_2.1.x86_64
hth
Regards
Stefan

Related

How to create a command in linux from a bash executable when my program uses an internal database? [duplicate]

How do I get the path of the directory in which a Bash script is located, inside that script?
I want to use a Bash script as a launcher for another application. I want to change the working directory to the one where the Bash script is located, so I can operate on the files in that directory, like so:
$ ./application
#!/usr/bin/env bash
SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
is a useful one-liner which will give you the full directory name of the script no matter where it is being called from.
It will work as long as the last component of the path used to find the script is not a symlink (directory links are OK). If you also want to resolve any links to the script itself, you need a multi-line solution:
#!/usr/bin/env bash
SOURCE=${BASH_SOURCE[0]}
while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
SOURCE=$(readlink "$SOURCE")
[[ $SOURCE != /* ]] && SOURCE=$DIR/$SOURCE # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
done
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
This last one will work with any combination of aliases, source, bash -c, symlinks, etc.
Beware: if you cd to a different directory before running this snippet, the result may be incorrect!
Also, watch out for $CDPATH gotchas, and stderr output side effects if the user has smartly overridden cd to redirect output to stderr instead (including escape sequences, such as when calling update_terminal_cwd >&2 on Mac). Adding >/dev/null 2>&1 at the end of your cd command will take care of both possibilities.
To understand how it works, try running this more verbose form:
#!/usr/bin/env bash
SOURCE=${BASH_SOURCE[0]}
while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
TARGET=$(readlink "$SOURCE")
if [[ $TARGET == /* ]]; then
echo "SOURCE '$SOURCE' is an absolute symlink to '$TARGET'"
SOURCE=$TARGET
else
DIR=$( dirname "$SOURCE" )
echo "SOURCE '$SOURCE' is a relative symlink to '$TARGET' (relative to '$DIR')"
SOURCE=$DIR/$TARGET # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
fi
done
echo "SOURCE is '$SOURCE'"
RDIR=$( dirname "$SOURCE" )
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
if [ "$DIR" != "$RDIR" ]; then
echo "DIR '$RDIR' resolves to '$DIR'"
fi
echo "DIR is '$DIR'"
And it will print something like:
SOURCE './scriptdir.sh' is a relative symlink to 'sym2/scriptdir.sh' (relative to '.')
SOURCE is './sym2/scriptdir.sh'
DIR './sym2' resolves to '/home/ubuntu/dotfiles/fo fo/real/real1/real2'
DIR is '/home/ubuntu/dotfiles/fo fo/real/real1/real2'
Use dirname "$0":
#!/usr/bin/env bash
echo "The script you are running has basename $( basename -- "$0"; ), dirname $( dirname -- "$0"; )";
echo "The present working directory is $( pwd; )";
Using pwd alone will not work if you are not running the script from the directory it is contained in.
[matt#server1 ~]$ pwd
/home/matt
[matt#server1 ~]$ ./test2.sh
The script you are running has basename test2.sh, dirname .
The present working directory is /home/matt
[matt#server1 ~]$ cd /tmp
[matt#server1 tmp]$ ~/test2.sh
The script you are running has basename test2.sh, dirname /home/matt
The present working directory is /tmp
The dirname command is the most basic, simply parsing the path up to the filename off of the $0 (script name) variable:
dirname -- "$0";
But, as matt b pointed out, the path returned is different depending on how the script is called. pwd doesn't do the job because that only tells you what the current directory is, not what directory the script resides in. Additionally, if a symbolic link to a script is executed, you're going to get a (probably relative) path to where the link resides, not the actual script.
Some others have mentioned the readlink command, but at its simplest, you can use:
dirname -- "$( readlink -f -- "$0"; )";
readlink will resolve the script path to an absolute path from the root of the filesystem. So, any paths containing single or double dots, tildes and/or symbolic links will be resolved to a full path.
Here's a script demonstrating each of these, whatdir.sh:
#!/usr/bin/env bash
echo "pwd: `pwd`"
echo "\$0: $0"
echo "basename: `basename -- "$0"`"
echo "dirname: `dirname -- "$0"`"
echo "dirname/readlink: $( dirname -- "$( readlink -f -- "$0"; )"; )"
Running this script in my home dir, using a relative path:
>>>$ ./whatdir.sh
pwd: /Users/phatblat
$0: ./whatdir.sh
basename: whatdir.sh
dirname: .
dirname/readlink: /Users/phatblat
Again, but using the full path to the script:
>>>$ /Users/phatblat/whatdir.sh
pwd: /Users/phatblat
$0: /Users/phatblat/whatdir.sh
basename: whatdir.sh
dirname: /Users/phatblat
dirname/readlink: /Users/phatblat
Now changing directories:
>>>$ cd /tmp
>>>$ ~/whatdir.sh
pwd: /tmp
$0: /Users/phatblat/whatdir.sh
basename: whatdir.sh
dirname: /Users/phatblat
dirname/readlink: /Users/phatblat
And finally using a symbolic link to execute the script:
>>>$ ln -s ~/whatdir.sh whatdirlink.sh
>>>$ ./whatdirlink.sh
pwd: /tmp
$0: ./whatdirlink.sh
basename: whatdirlink.sh
dirname: .
dirname/readlink: /Users/phatblat
There is however one case where this doesn't work, when the script is sourced (instead of executed) in bash:
>>>$ cd /tmp
>>>$ . ~/whatdir.sh
pwd: /tmp
$0: bash
basename: bash
dirname: .
dirname/readlink: /tmp
pushd . > '/dev/null';
SCRIPT_PATH="${BASH_SOURCE[0]:-$0}";
while [ -h "$SCRIPT_PATH" ];
do
cd "$( dirname -- "$SCRIPT_PATH"; )";
SCRIPT_PATH="$( readlink -f -- "$SCRIPT_PATH"; )";
done
cd "$( dirname -- "$SCRIPT_PATH"; )" > '/dev/null';
SCRIPT_PATH="$( pwd; )";
popd > '/dev/null';
It works for all versions, including
when called via multiple depth soft link,
when the file it
when script called by command "source" aka . (dot) operator.
when arg $0 is modified from caller.
"./script"
"/full/path/to/script"
"/some/path/../../another/path/script"
"./some/folder/script"
Alternatively, if the Bash script itself is a relative symlink you want to follow it and return the full path of the linked-to script:
pushd . > '/dev/null';
SCRIPT_PATH="${BASH_SOURCE[0]:-$0}";
while [ -h "$SCRIPT_PATH" ];
do
cd "$( dirname -- "$SCRIPT_PATH"; )";
SCRIPT_PATH="$( readlink -f -- "$SCRIPT_PATH"; )";
done
cd "$( dirname -- "$SCRIPT_PATH"; )" > '/dev/null';
SCRIPT_PATH="$( pwd; )";
popd > '/dev/null';
SCRIPT_PATH is given in full path, no matter how it is called.
Just make sure you locate this at start of the script.
You can use $BASH_SOURCE:
#!/usr/bin/env bash
scriptdir="$( dirname -- "$BASH_SOURCE"; )";
Note that you need to use #!/bin/bash and not #!/bin/sh since it's a Bash extension.
Here is an easy-to-remember script:
DIR="$( dirname -- "${BASH_SOURCE[0]}"; )"; # Get the directory name
DIR="$( realpath -e -- "$DIR"; )"; # Resolve its full path if need be
Short answer:
"`dirname -- "$0";`"
or (preferably):
"$( dirname -- "$0"; )"
This should do it:
DIR="$(dirname "$(realpath "$0")")"
This works with symlinks and spaces in path.
Please see the man pages for dirname and realpath.
Please add a comment on how to support MacOS. I'm sorry I can verify it.
pwd can be used to find the current working directory, and dirname to find the directory of a particular file (command that was run, is $0, so dirname $0 should give you the directory of the current script).
However, dirname gives precisely the directory portion of the filename, which more likely than not is going to be relative to the current working directory. If your script needs to change directory for some reason, then the output from dirname becomes meaningless.
I suggest the following:
#!/usr/bin/env bash
reldir="$( dirname -- "$0"; )";
cd "$reldir";
directory="$( pwd; )";
echo "Directory is ${directory}";
This way, you get an absolute, rather than a relative directory.
Since the script will be run in a separate Bash instance, there isn't any need to restore the working directory afterwards, but if you do want to change back in your script for some reason, you can easily assign the value of pwd to a variable before you change directory, for future use.
Although just
cd "$( dirname -- "$0"; )";
solves the specific scenario in the question, I find having the absolute path to more more useful generally.
SCRIPT_DIR=$( cd ${0%/*} && pwd -P )
I don't think this is as easy as others have made it out to be. pwd doesn't work, as the current directory is not necessarily the directory with the script. $0 doesn't always have the information either. Consider the following three ways to invoke a script:
./script
/usr/bin/script
script
In the first and third ways $0 doesn't have the full path information. In the second and third, pwd does not work. The only way to get the directory in the third way would be to run through the path and find the file with the correct match. Basically the code would have to redo what the OS does.
One way to do what you are asking would be to just hardcode the data in the /usr/share directory, and reference it by its full path. Data shoudn't be in the /usr/bin directory anyway, so this is probably the thing to do.
This gets the current working directory on Mac OS X v10.6.6 (Snow Leopard):
DIR=$(cd "$(dirname "$0")"; pwd)
$(dirname "$(readlink -f "$BASH_SOURCE")")
This is Linux specific, but you could use:
SELF=$(readlink /proc/$$/fd/255)
Here is a POSIX compliant one-liner:
SCRIPT_PATH=`dirname "$0"`; SCRIPT_PATH=`eval "cd \"$SCRIPT_PATH\" && pwd"`
# test
echo $SCRIPT_PATH
The shortest and most elegant way to do this is:
#!/bin/bash
DIRECTORY=$(cd `dirname $0` && pwd)
echo $DIRECTORY
This would work on all platforms and is super clean.
More details can be found in "Which directory is that bash script in?".
Summary:
FULL_PATH_TO_SCRIPT="$(realpath "${BASH_SOURCE[-1]}")"
# OR, if you do NOT need it to work for **sourced** scripts too:
# FULL_PATH_TO_SCRIPT="$(realpath "$0")"
# OR, depending on which path you want, in case of nested `source` calls
# FULL_PATH_TO_SCRIPT="$(realpath "${BASH_SOURCE[0]}")"
# OR, add `-s` to NOT expand symlinks in the path:
# FULL_PATH_TO_SCRIPT="$(realpath -s "${BASH_SOURCE[-1]}")"
SCRIPT_DIRECTORY="$(dirname "$FULL_PATH_TO_SCRIPT")"
SCRIPT_FILENAME="$(basename "$FULL_PATH_TO_SCRIPT")"
Details:
How to obtain the full file path, full directory, and base filename of any script being run OR sourced...
...even when the called script is called from within another bash function or script, or when nested sourcing is being used!
For many cases, all you need to acquire is the full path to the script you just called. This can be easily accomplished using realpath. Note that realpath is part of GNU coreutils. If you don't have it already installed (it comes default on Ubuntu), you can install it with sudo apt update && sudo apt install coreutils.
get_script_path.sh (for the latest version of this script, see get_script_path.sh in my eRCaGuy_hello_world repo):
#!/bin/bash
# A. Obtain the full path, and expand (walk down) symbolic links
# A.1. `"$0"` works only if the file is **run**, but NOT if it is **sourced**.
# FULL_PATH_TO_SCRIPT="$(realpath "$0")"
# A.2. `"${BASH_SOURCE[-1]}"` works whether the file is sourced OR run, and even
# if the script is called from within another bash function!
# NB: if `"${BASH_SOURCE[-1]}"` doesn't give you quite what you want, use
# `"${BASH_SOURCE[0]}"` instead in order to get the first element from the array.
FULL_PATH_TO_SCRIPT="$(realpath "${BASH_SOURCE[-1]}")"
# B.1. `"$0"` works only if the file is **run**, but NOT if it is **sourced**.
# FULL_PATH_TO_SCRIPT_KEEP_SYMLINKS="$(realpath -s "$0")"
# B.2. `"${BASH_SOURCE[-1]}"` works whether the file is sourced OR run, and even
# if the script is called from within another bash function!
# NB: if `"${BASH_SOURCE[-1]}"` doesn't give you quite what you want, use
# `"${BASH_SOURCE[0]}"` instead in order to get the first element from the array.
FULL_PATH_TO_SCRIPT_KEEP_SYMLINKS="$(realpath -s "${BASH_SOURCE[-1]}")"
# You can then also get the full path to the directory, and the base
# filename, like this:
SCRIPT_DIRECTORY="$(dirname "$FULL_PATH_TO_SCRIPT")"
SCRIPT_FILENAME="$(basename "$FULL_PATH_TO_SCRIPT")"
# Now print it all out
echo "FULL_PATH_TO_SCRIPT = \"$FULL_PATH_TO_SCRIPT\""
echo "SCRIPT_DIRECTORY = \"$SCRIPT_DIRECTORY\""
echo "SCRIPT_FILENAME = \"$SCRIPT_FILENAME\""
IMPORTANT note on nested source calls: if "${BASH_SOURCE[-1]}" above doesn't give you quite what you want, try using "${BASH_SOURCE[0]}" instead. The first (0) index gives you the first entry in the array, and the last (-1) index gives you the last last entry in the array. Depending on what it is you're after, you may actually want the first entry. I discovered this to be the case when I sourced ~/.bashrc with . ~/.bashrc, which sourced ~/.bash_aliases with . ~/.bash_aliases, and I wanted the realpath (with expanded symlinks) to the ~/.bash_aliases file, NOT to the ~/.bashrc file. Since these are nested source calls, using "${BASH_SOURCE[0]}" gave me what I wanted: the expanded path to ~/.bash_aliases! Using "${BASH_SOURCE[-1]}", however, gave me what I did not want: the expanded path to ~/.bashrc.
Example command and output:
Running the script:
~/GS/dev/eRCaGuy_hello_world/bash$ ./get_script_path.sh
FULL_PATH_TO_SCRIPT = "/home/gabriel/GS/dev/eRCaGuy_hello_world/bash/get_script_path.sh"
SCRIPT_DIRECTORY = "/home/gabriel/GS/dev/eRCaGuy_hello_world/bash"
SCRIPT_FILENAME = "get_script_path.sh"
Sourcing the script with . get_script_path.sh or source get_script_path.sh (the result is the exact same as above because I used "${BASH_SOURCE[-1]}" in the script instead of "$0"):
~/GS/dev/eRCaGuy_hello_world/bash$ . get_script_path.sh
FULL_PATH_TO_SCRIPT = "/home/gabriel/GS/dev/eRCaGuy_hello_world/bash/get_script_path.sh"
SCRIPT_DIRECTORY = "/home/gabriel/GS/dev/eRCaGuy_hello_world/bash"
SCRIPT_FILENAME = "get_script_path.sh"
If you use "$0" in the script instead of "${BASH_SOURCE[-1]}", you'll get the same output as above when running the script, but this undesired output instead when sourcing the script:
~/GS/dev/eRCaGuy_hello_world/bash$ . get_script_path.sh
FULL_PATH_TO_SCRIPT = "/bin/bash"
SCRIPT_DIRECTORY = "/bin"
SCRIPT_FILENAME = "bash"
And, apparently if you use "$BASH_SOURCE" instead of "${BASH_SOURCE[-1]}", it will not work if the script is called from within another bash function. So, using "${BASH_SOURCE[-1]}" is therefore the best way to do it, as it solves both of these problems! See the references below.
Difference between realpath and realpath -s:
Note that realpath also successfully walks down symbolic links to determine and point to their targets rather than pointing to the symbolic link. If you do NOT want this behavior (sometimes I don't), then add -s to the realpath command above, making that line look like this instead:
# Obtain the full path, but do NOT expand (walk down) symbolic links; in
# other words: **keep** the symlinks as part of the path!
FULL_PATH_TO_SCRIPT="$(realpath -s "${BASH_SOURCE[-1]}")"
This way, symbolic links are NOT expanded. Rather, they are left as-is, as symbolic links in the full path.
The code above is now part of my eRCaGuy_hello_world repo in this file here: bash/get_script_path.sh. Reference and run this file for full examples both with and withOUT symlinks in the paths. See the bottom of the file for example output in both cases.
References:
How to retrieve absolute path given relative
taught me about the BASH_SOURCE variable: Unix & Linux: determining path to sourced shell script
taught me that BASH_SOURCE is actually an array, and we want the last element from it for it to work as expected inside a function (hence why I used "${BASH_SOURCE[-1]}" in my code here): Unix & Linux: determining path to sourced shell script
man bash --> search for BASH_SOURCE:
BASH_SOURCE
An array variable whose members are the source filenames where the corresponding shell function names in the FUNCNAME array variable are defined. The shell function ${FUNCNAME[$i]} is defined in the file ${BASH_SOURCE[$i]} and called from ${BASH_SOURCE[$i+1]}.
See also:
[my answer] Unix & Linux: determining path to sourced shell script
#!/bin/sh
PRG="$0"
# need this for relative symlinks
while [ -h "$PRG" ] ; do
PRG=`readlink "$PRG"`
done
scriptdir=`dirname "$PRG"`
Here is the simple, correct way:
actual_path=$(readlink -f "${BASH_SOURCE[0]}")
script_dir=$(dirname "$actual_path")
Explanation:
${BASH_SOURCE[0]} - the full path to the script. The value of this will be correct even when the script is being sourced, e.g. source <(echo 'echo $0') prints bash, while replacing it with ${BASH_SOURCE[0]} will print the full path of the script. (Of course, this assumes you're OK taking a dependency on Bash.)
readlink -f - Recursively resolves any symlinks in the specified path. This is a GNU extension, and not available on (for example) BSD systems. If you're running a Mac, you can use Homebrew to install GNU coreutils and supplant this with greadlink -f.
And of course dirname gets the parent directory of the path.
I tried all of these and none worked. One was very close, but it had a tiny bug that broke it badly; they forgot to wrap the path in quotation marks.
Also a lot of people assume you're running the script from a shell, so they forget when you open a new script it defaults to your home.
Try this directory on for size:
/var/No one/Thought/About Spaces Being/In a Directory/Name/And Here's your file.text
This gets it right regardless how or where you run it:
#!/bin/bash
echo "pwd: `pwd`"
echo "\$0: $0"
echo "basename: `basename "$0"`"
echo "dirname: `dirname "$0"`"
So to make it actually useful, here's how to change to the directory of the running script:
cd "`dirname "$0"`"
This is a slight revision to the solution e-satis and 3bcdnlklvc04a pointed out in their answer:
SCRIPT_DIR=''
pushd "$(dirname "$(readlink -f "$BASH_SOURCE")")" > /dev/null && {
SCRIPT_DIR="$PWD"
popd > /dev/null
}
This should still work in all the cases they listed.
This will prevent popd after a failed pushd. Thanks to konsolebox.
Try using:
real=$(realpath "$(dirname "$0")")
I would use something like this:
# Retrieve the full pathname of the called script
scriptPath=$(which $0)
# Check whether the path is a link or not
if [ -L $scriptPath ]; then
# It is a link then retrieve the target path and get the directory name
sourceDir=$(dirname $(readlink -f $scriptPath))
else
# Otherwise just get the directory name of the script path
sourceDir=$(dirname $scriptPath)
fi
For systems having GNU coreutils readlink (for example, Linux):
$(readlink -f "$(dirname "$0")")
There's no need to use BASH_SOURCE when $0 contains the script filename.
$_ is worth mentioning as an alternative to $0. If you're running a script from Bash, the accepted answer can be shortened to:
DIR="$( dirname "$_" )"
Note that this has to be the first statement in your script.
These are short ways to get script information:
Folders and files:
Script: "/tmp/src dir/test.sh"
Calling folder: "/tmp/src dir/other"
Using these commands:
echo Script-Dir : `dirname "$(realpath $0)"`
echo Script-Dir : $( cd ${0%/*} && pwd -P )
echo Script-Dir : $(dirname "$(readlink -f "$0")")
echo
echo Script-Name : `basename "$(realpath $0)"`
echo Script-Name : `basename $0`
echo
echo Script-Dir-Relative : `dirname "$BASH_SOURCE"`
echo Script-Dir-Relative : `dirname $0`
echo
echo Calling-Dir : `pwd`
And I got this output:
Script-Dir : /tmp/src dir
Script-Dir : /tmp/src dir
Script-Dir : /tmp/src dir
Script-Name : test.sh
Script-Name : test.sh
Script-Dir-Relative : ..
Script-Dir-Relative : ..
Calling-Dir : /tmp/src dir/other
Also see: https://pastebin.com/J8KjxrPF
This works in Bash 3.2:
path="$( dirname "$( which "$0" )" )"
If you have a ~/bin directory in your $PATH, you have A inside this directory. It sources the script ~/bin/lib/B. You know where the included script is relative to the original one, in the lib subdirectory, but not where it is relative to the user's current directory.
This is solved by the following (inside A):
source "$( dirname "$( which "$0" )" )/lib/B"
It doesn't matter where the user is or how he/she calls the script. This will always work.
I've compared many of the answers given, and came up with some more compact solutions. These seem to handle all of the crazy edge cases that arise from your favorite combination of:
Absolute paths or relative paths
File and directory soft links
Invocation as script, bash script, bash -c script, source script, or . script
Spaces, tabs, newlines, Unicode, etc. in directories and/or filename
Filenames beginning with a hyphen
If you're running from Linux, it seems that using the proc handle is the best solution to locate the fully resolved source of the currently running script (in an interactive session, the link points to the respective /dev/pts/X):
resolved="$(readlink /proc/$$/fd/255 && echo X)" && resolved="${resolved%$'\nX'}"
This has a small bit of ugliness to it, but the fix is compact and easy to understand. We aren't using bash primitives only, but I'm okay with that because readlink simplifies the task considerably. The echo X adds an X to the end of the variable string so that any trailing whitespace in the filename doesn't get eaten, and the parameter substitution ${VAR%X} at the end of the line gets rid of the X. Because readlink adds a newline of its own (which would normally be eaten in the command substitution if not for our previous trickery), we have to get rid of that, too. This is most easily accomplished using the $'' quoting scheme, which lets us use escape sequences such as \n to represent newlines (this is also how you can easily make deviously named directories and files).
The above should cover your needs for locating the currently running script on Linux, but if you don't have the proc filesystem at your disposal, or if you're trying to locate the fully resolved path of some other file, then maybe you'll find the below code helpful. It's only a slight modification from the above one-liner. If you're playing around with strange directory/filenames, checking the output with both ls and readlink is informative, as ls will output "simplified" paths, substituting ? for things like newlines.
absolute_path=$(readlink -e -- "${BASH_SOURCE[0]}" && echo x) && absolute_path=${absolute_path%?x}
dir=$(dirname -- "$absolute_path" && echo x) && dir=${dir%?x}
file=$(basename -- "$absolute_path" && echo x) && file=${file%?x}
ls -l -- "$dir/$file"
printf '$absolute_path: "%s"\n' "$absolute_path"
I believe I've got this one. I'm late to the party, but I think some will appreciate it being here if they come across this thread. The comments should explain:
#!/bin/sh # dash bash ksh # !zsh (issues). G. Nixon, 12/2013. Public domain.
## 'linkread' or 'fullpath' or (you choose) is a little tool to recursively
## dereference symbolic links (ala 'readlink') until the originating file
## is found. This is effectively the same function provided in stdlib.h as
## 'realpath' and on the command line in GNU 'readlink -f'.
## Neither of these tools, however, are particularly accessible on the many
## systems that do not have the GNU implementation of readlink, nor ship
## with a system compiler (not to mention the requisite knowledge of C).
## This script is written with portability and (to the extent possible, speed)
## in mind, hence the use of printf for echo and case statements where they
## can be substituded for test, though I've had to scale back a bit on that.
## It is (to the best of my knowledge) written in standard POSIX shell, and
## has been tested with bash-as-bin-sh, dash, and ksh93. zsh seems to have
## issues with it, though I'm not sure why; so probably best to avoid for now.
## Particularly useful (in fact, the reason I wrote this) is the fact that
## it can be used within a shell script to find the path of the script itself.
## (I am sure the shell knows this already; but most likely for the sake of
## security it is not made readily available. The implementation of "$0"
## specificies that the $0 must be the location of **last** symbolic link in
## a chain, or wherever it resides in the path.) This can be used for some
## ...interesting things, like self-duplicating and self-modifiying scripts.
## Currently supported are three errors: whether the file specified exists
## (ala ENOENT), whether its target exists/is accessible; and the special
## case of when a sybolic link references itself "foo -> foo": a common error
## for beginners, since 'ln' does not produce an error if the order of link
## and target are reversed on the command line. (See POSIX signal ELOOP.)
## It would probably be rather simple to write to use this as a basis for
## a pure shell implementation of the 'symlinks' util included with Linux.
## As an aside, the amount of code below **completely** belies the amount
## effort it took to get this right -- but I guess that's coding for you.
##===-------------------------------------------------------------------===##
for argv; do :; done # Last parameter on command line, for options parsing.
## Error messages. Use functions so that we can sub in when the error occurs.
recurses(){ printf "Self-referential:\n\t$argv ->\n\t$argv\n" ;}
dangling(){ printf "Broken symlink:\n\t$argv ->\n\t"$(readlink "$argv")"\n" ;}
errnoent(){ printf "No such file: "$#"\n" ;} # Borrow a horrible signal name.
# Probably best not to install as 'pathfull', if you can avoid it.
pathfull(){ cd "$(dirname "$#")"; link="$(readlink "$(basename "$#")")"
## 'test and 'ls' report different status for bad symlinks, so we use this.
if [ ! -e "$#" ]; then if $(ls -d "$#" 2>/dev/null) 2>/dev/null; then
errnoent 1>&2; exit 1; elif [ ! -e "$#" -a "$link" = "$#" ]; then
recurses 1>&2; exit 1; elif [ ! -e "$#" ] && [ ! -z "$link" ]; then
dangling 1>&2; exit 1; fi
fi
## Not a link, but there might be one in the path, so 'cd' and 'pwd'.
if [ -z "$link" ]; then if [ "$(dirname "$#" | cut -c1)" = '/' ]; then
printf "$#\n"; exit 0; else printf "$(pwd)/$(basename "$#")\n"; fi; exit 0
fi
## Walk the symlinks back to the origin. Calls itself recursivly as needed.
while [ "$link" ]; do
cd "$(dirname "$link")"; newlink="$(readlink "$(basename "$link")")"
case "$newlink" in
"$link") dangling 1>&2 && exit 1 ;;
'') printf "$(pwd)/$(basename "$link")\n"; exit 0 ;;
*) link="$newlink" && pathfull "$link" ;;
esac
done
printf "$(pwd)/$(basename "$newlink")\n"
}
## Demo. Install somewhere deep in the filesystem, then symlink somewhere
## else, symlink again (maybe with a different name) elsewhere, and link
## back into the directory you started in (or something.) The absolute path
## of the script will always be reported in the usage, along with "$0".
if [ -z "$argv" ]; then scriptname="$(pathfull "$0")"
# Yay ANSI l33t codes! Fancy.
printf "\n\033[3mfrom/as: \033[4m$0\033[0m\n\n\033[1mUSAGE:\033[0m "
printf "\033[4m$scriptname\033[24m [ link | file | dir ]\n\n "
printf "Recursive readlink for the authoritative file, symlink after "
printf "symlink.\n\n\n \033[4m$scriptname\033[24m\n\n "
printf " From within an invocation of a script, locate the script's "
printf "own file\n (no matter where it has been linked or "
printf "from where it is being called).\n\n"
else pathfull "$#"
fi
Try the following cross-compatible solution:
CWD="$(cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
As the commands such as realpath or readlink could be not available (depending on the operating system).
Note: In Bash, it's recommended to use ${BASH_SOURCE[0]} instead of $0, otherwise path can break when sourcing the file (source/.).
Alternatively you can try the following function in Bash:
realpath () {
[[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
}
This function takes one argument. If argument has already absolute path, print it as it is, otherwise print $PWD variable + filename argument (without ./ prefix).
Related:
How can I set the current working directory to the directory of the script in Bash?
Bash script absolute path with OS X
Reliable way for a Bash script to get the full path to itself

How do I get the absolute directory of a file in Bash?

I have written a Bash script that takes an input file as an argument and reads it.
This file contains some paths (relative to its location) to other files.
I would like the script to go to the folder containing the input file, to execute further commands.
In Linux, how do I get the folder (and just the folder) from an input file?
To get the full path use:
readlink -f relative/path/to/file
To get the directory of a file:
dirname relative/path/to/file
You can also combine the two:
dirname $(readlink -f relative/path/to/file)
If readlink -f is not available on your system you can use this*:
function myreadlink() {
(
cd "$(dirname $1)" # or cd "${1%/*}"
echo "$PWD/$(basename $1)" # or echo "$PWD/${1##*/}"
)
}
Note that if you only need to move to a directory of a file specified as a relative path, you don't need to know the absolute path, a relative path is perfectly legal, so just use:
cd $(dirname relative/path/to/file)
if you wish to go back (while the script is running) to the original path, use pushd instead of cd, and popd when you are done.
* While myreadlink above is good enough in the context of this question, it has some limitation relative to the readlink tool suggested above. For example it doesn't correctly follow a link to a file with different basename.
Take a look at realpath which is available on GNU/Linux, FreeBSD and NetBSD, but not OpenBSD 6.8. I use something like:
CONTAININGDIR=$(realpath ${FILEPATH%/*})
to do what it sounds like you're trying to do.
This will work for both file and folder:
absPath(){
if [[ -d "$1" ]]; then
cd "$1"
echo "$(pwd -P)"
else
cd "$(dirname "$1")"
echo "$(pwd -P)/$(basename "$1")"
fi
}
$cat abs.sh
#!/bin/bash
echo "$(cd "$(dirname "$1")"; pwd -P)"
Some explanations:
This script get relative path as argument "$1"
Then we get dirname part of that path (you can pass either dir or file to this script): dirname "$1"
Then we cd "$(dirname "$1"); into this relative dir
pwd -P and get absolute path. The -P option will avoid symlinks
As final step we echo it
Then run your script:
abs.sh your_file.txt
Try our new Bash library product realpath-lib over at GitHub that we have given to the community for free and unencumbered use. It's clean, simple and well documented so it's great to learn from. You can do:
get_realpath <absolute|relative|symlink|local file path>
This function is the core of the library:
if [[ -f "$1" ]]
then
# file *must* exist
if cd "$(echo "${1%/*}")" &>/dev/null
then
# file *may* not be local
# exception is ./file.ext
# try 'cd .; cd -;' *works!*
local tmppwd="$PWD"
cd - &>/dev/null
else
# file *must* be local
local tmppwd="$PWD"
fi
else
# file *cannot* exist
return 1 # failure
fi
# reassemble realpath
echo "$tmppwd"/"${1##*/}"
return 0 # success
}
It's Bash 4+, does not require any dependencies and also provides get_dirname, get_filename, get_stemname and validate_path.
Problem with the above answer comes with files input with "./" like "./my-file.txt"
Workaround (of many):
myfile="./somefile.txt"
FOLDER="$(dirname $(readlink -f "${ARG}"))"
echo ${FOLDER}
I have been using readlink -f works on linux
so
FULL_PATH=$(readlink -f filename)
DIR=$(dirname $FULL_PATH)
PWD=$(pwd)
cd $DIR
#<do more work>
cd $PWD

How to convert ".." in path names to absolute name in a bash script?

How to convert the .. in the path names to absolute path names in a bash script. That is, if I have a path /home/nohsib/dvc/../bop, I want this to be changed to the path without dots in it, in this case /home/nohsib/bop
How can I do that?
What you're looking for is readlink:
absolute_path=$(readlink -m /home/nohsib/dvc/../bop)
Please note: You need to use GNU's readlink implementation which offers the "-m" option. BSD's readlink for example does not.
Try:
ABSOLUTE_PATH=$(cd /home/nohsib/dvc/../bop; pwd)
One issue with using :
ABSOLUTE_PATH=$(cd ${possibleDirectory}; pwd)
is that if ${possibleDirectory} doesn't exist, ABSOLUTE_PATH will then be set to the current directory. Which is probably NOT what you want or expect.
I think using this version may be more desirable in general:
ABSOLUTE_PATH=$(cd ${possibleDirectory} && pwd)
If ${possibleDirectory} does not exist or is not accessible, due to missing directory access permissions, ABSOLUTE_PATH will contain the empty string.
The advantage of this is that you can then test for the empty string or let it fail naturally, depending on the circumstances. Defaulting to the current directory in the case of a failed 'cd' command may lead to very unexpected and possibly disastrous results (e.g. rm -rf "$ABSOLUTE_PATH" )
If you want to do it without following any symlinks, then try using realpath with option -s:
$ realpath -s /home/nohsib/dvc/../bop
/home/nohsib/bop
Note that with realpath, normally all but the last component must exist. So for the above to work, the following must all be present in the file system:
/home
/home/nohsib
/home/nohsib/dvc
But you can bypass that requirement using the -m option.
$ realpath -sm /home/nohsib/dvc/../bop
/home/nohsib/bop
(Note realpath is not available on all systems, especially older non-Debian systems. For those working on embedded Linux, unfortunately Busybox realpath doesn't support the -s or -m switches.)
Use
echo Absolute path: $(cd $1; pwd)
Just an additional note, if your current path is under a symlink, you can resolve the true path with this:
pwd -P
To solve your specific problem, this will issue a cd command to change directory to the path without the '..' in it. Note you will be in the same folder, just with the correct path:
cd `pwd -P`
As an alternative to GNU's readlink and realpath, I had created functions as well that would run in scripts independent of external commands like pwd and stuffs.
http://www.linuxquestions.org/questions/blog/konsolebox-210384/getting-absolute-paths-of-unix-directories-and-filenames-in-shell-scripts-3956/
One of those is this one. It will save the absolute path to $__. I used read there to be safe from pathname expansion.
function getabspath {
local -a T1 T2
local -i I=0
local IFS=/ A
case "$1" in
/*)
read -r -a T1 <<< "$1"
;;
*)
read -r -a T1 <<< "/$PWD/$1"
;;
esac
T2=()
for A in "${T1[#]}"; do
case "$A" in
..)
[[ I -ne 0 ]] && unset T2\[--I\]
continue
;;
.|'')
continue
;;
esac
T2[I++]=$A
done
case "$1" in
*/)
[[ I -ne 0 ]] && __="/${T2[*]}/" || __=/
;;
*)
[[ I -ne 0 ]] && __="/${T2[*]}" || __=/.
;;
esac
}
one good solution under a shell would be :
readlink -ev mypathname
It prints out the full path name with dots resolved.
Relative paths must be converted into absolute, it is NOT required to exist!
Neither symlinks should be resolved.
Try this one-line python solution:
abs_path=$(python -c "import os; print(os.path.abspath(\"$rel_path\"))")
in your example:
python -c "import os; print(os.path.abspath(\"/home/nohsib/dvc/../bop\"))"
returns /home/nohsib/bop
Try this (assuming your relative path is stored in the variable $rel_path):
echo "`cd $rel_path; pwd`"

How to get full path of a file?

Is there an easy way I can print the full path of file.txt ?
file.txt = /nfs/an/disks/jj/home/dir/file.txt
The <command>
dir> <command> file.txt
should print
/nfs/an/disks/jj/home/dir/file.txt
Use readlink:
readlink -f file.txt
I suppose you are using Linux.
I found a utility called realpath in coreutils 8.15.
realpath -s file.txt
/data/ail_data/transformed_binaries/coreutils/test_folder_realpath/file.txt
Since the question is about how to get the full/absolute path of a file and not about how to get the target of symlinks, use -s or --no-symlinks which means don't expand symlinks.
As per #styrofoam-fly and #arch-standton comments, realpath alone doesn't check for file existence, to solve this add the e argument: realpath -e file
The following usually does the trick:
echo "$(cd "$(dirname "$1")" && pwd -P)/$(basename "$1")"
I know there's an easier way that this, but darned if I can find it...
jcomeau#intrepid:~$ python -c 'import os; print(os.path.abspath("cat.wav"))'
/home/jcomeau/cat.wav
jcomeau#intrepid:~$ ls $PWD/cat.wav
/home/jcomeau/cat.wav
On Windows:
Holding Shift and right clicking on a file in Windows Explorer gives you an option called Copy as Path.
This will copy the full path of the file to clipboard.
On Linux:
You can use the command realpath yourfile to get the full path of a file as suggested by others.
find $PWD -type f | grep "filename"
or
find $PWD -type f -name "*filename*"
If you are in the same directory as the file:
ls "`pwd`/file.txt"
Replace file.txt with your target filename.
I know that this is an old question now, but just to add to the information here:
The Linux command which can be used to find the filepath of a command file, i.e.
$ which ls
/bin/ls
There are some caveats to this; please see https://www.cyberciti.biz/faq/how-do-i-find-the-path-to-a-command-file/.
You could use the fpn (full path name) script:
% pwd
/Users/adamatan/bins/scripts/fpn
% ls
LICENSE README.md fpn.py
% fpn *
/Users/adamatan/bins/scripts/fpn/LICENSE
/Users/adamatan/bins/scripts/fpn/README.md
/Users/adamatan/bins/scripts/fpn/fpn.py
fpn is not a standard Linux package, but it's a free and open github project and you could set it up in a minute.
Works on Mac, Linux, *nix:
This will give you a quoted csv of all files in the current dir:
ls | xargs -I {} echo "$(pwd -P)/{}" | xargs | sed 's/ /","/g'
The output of this can be easily copied into a python list or any similar data structure.
echo $(cd $(dirname "$1") && pwd -P)/$(basename "$1")
This is explanation of what is going on at #ZeRemz's answer:
This script get relative path as argument "$1"
Then we get dirname part of that path (you can pass either dir or file to this script): dirname "$1"
Then we cd "$(dirname "$1") into this relative dir
&& pwd -P and get absolute path for it. -P option will avoid all symlinks
After that we append basename to absolute path: $(basename "$1")
As final step we echo it
You may use this function. If the file name is given without relative path, then it is assumed to be present in the current working directory:
abspath() { old=`pwd`;new=$(dirname "$1");if [ "$new" != "." ]; then cd $new; fi;file=`pwd`/$(basename "$1");cd $old;echo $file; }
Usage:
$ abspath file.txt
/I/am/in/present/dir/file.txt
Usage with relative path:
$ abspath ../../some/dir/some-file.txt
/I/am/in/some/dir/some-file.txt
With spaces in file name:
$ abspath "../../some/dir/another file.txt"
/I/am/in/some/dir/another file.txt
You can save this in your shell.rc or just put in console
function absolute_path { echo "$PWD/$1"; }
alias ap="absolute_path"
example:
ap somefile.txt
will output
/home/user/somefile.txt
I was surprised no one mentioned located.
If you have the locate package installed, you don't even need to be in the directory with the file of interest.
Say I am looking for the full pathname of a setenv.sh script. This is how to find it.
$ locate setenv.sh
/home/davis/progs/devpost_aws_disaster_response/python/setenv.sh
/home/davis/progs/devpost_aws_disaster_response/webapp/setenv.sh
/home/davis/progs/eb_testy/setenv.sh
Note, it finds three scripts in this case, but if I wanted just one I
would do this:
$ locate *testy*setenv.sh
/home/davis/progs/eb_testy/setenv.sh
This solution uses commands that exist on Ubuntu 22.04, but generally exist on most other Linux distributions, unless they are just to hardcore for s'mores.
The shortest way to get the full path of a file on Linux or Mac is to use the ls command and the PWD environment variable.
<0.o> touch afile
<0.o> pwd
/adir
<0.o> ls $PWD/afile
/adir/afile
You can do the same thing with a directory variable of your own, say d.
<0.o> touch afile
<0.o> d=/adir
<0.o> ls $d/afile
/adir/afile
Notice that without flags ls <FILE> and echo <FILE> are equivalent (for valid names of files in the current directory), so if you're using echo for that, you can use ls instead if you want.
If the situation is reversed, so that you have the full path and want the filename, just use the basename command.
<0.o> touch afile
<0.o> basename $PWD/afile
afile
In a similar scenario, I'm launching a cshell script from some other location. For setting the correct absolute path of the script so that it runs in the designated directory only, I'm using the following code:
set script_dir = `pwd`/`dirname $0`
$0 stores the exact string how the script was executed.
For e.g. if the script was launched like this: $> ../../test/test.csh,
$script_dir will contain /home/abc/sandbox/v1/../../test
For Mac OS X, I replaced the utilities that come with the operating system and replaced them with a newer version of coreutils. This allows you to access tools like readlink -f (for absolute path to files) and realpath (absolute path to directories) on your Mac.
The Homebrew version appends a 'G' (for GNU Tools) in front of the command name -- so the equivalents become greadlink -f FILE and grealpath DIRECTORY.
Instructions for how to install the coreutils/GNU Tools on Mac OS X through Homebrew can be found in this StackExchange arcticle.
NB: The readlink -f and realpath commands should work out of the box for non-Mac Unix users.
I like many of the answers already given, but I have found this really useful, especially within a script to get the full path of a file, including following symlinks and relative references such as . and ..
dirname `readlink -e relative/path/to/file`
Which will return the full path of the file from the root path onwards.
This can be used in a script so that the script knows which path it is running from, which is useful in a repository clone which could be located anywhere on a machine.
basePath=`dirname \`readlink -e $0\``
I can then use the ${basePath} variable in my scripts to directly reference other scripts.
Hope this helps,
Dave
This worked pretty well for me. It doesn't rely on the file system (a pro/con depending on need) so it'll be fast; and, it should be portable to most any *NIX. It does assume the passed string is indeed relative to the PWD and not some other directory.
function abspath () {
echo $1 | awk '\
# Root parent directory refs to the PWD for replacement below
/^\.\.\// { sub("^", "./") } \
# Replace the symbolic PWD refs with the absolute PWD \
/^\.\// { sub("^\.", ENVIRON["PWD"])} \
# Print absolute paths \
/^\// {print} \'
}
This is naive, but I had to make it to be POSIX compliant. Requires permission to cd into the file's directory.
#!/bin/sh
if [ ${#} = 0 ]; then
echo "Error: 0 args. need 1" >&2
exit 1
fi
if [ -d ${1} ]; then
# Directory
base=$( cd ${1}; echo ${PWD##*/} )
dir=$( cd ${1}; echo ${PWD%${base}} )
if [ ${dir} = / ]; then
parentPath=${dir}
else
parentPath=${dir%/}
fi
if [ -z ${base} ] || [ -z ${parentPath} ]; then
if [ -n ${1} ]; then
fullPath=$( cd ${1}; echo ${PWD} )
else
echo "Error: unsupported scenario 1" >&2
exit 1
fi
fi
elif [ ${1%/*} = ${1} ]; then
if [ -f ./${1} ]; then
# File in current directory
base=$( echo ${1##*/} )
parentPath=$( echo ${PWD} )
else
echo "Error: unsupported scenario 2" >&2
exit 1
fi
elif [ -f ${1} ] && [ -d ${1%/*} ]; then
# File in directory
base=$( echo ${1##*/} )
parentPath=$( cd ${1%/*}; echo ${PWD} )
else
echo "Error: not file or directory" >&2
exit 1
fi
if [ ${parentPath} = / ]; then
fullPath=${fullPath:-${parentPath}${base}}
fi
fullPath=${fullPath:-${parentPath}/${base}}
if [ ! -e ${fullPath} ]; then
echo "Error: does not exist" >&2
exit 1
fi
echo ${fullPath}
This works with both Linux and Mac OSX:
echo $(pwd)$/$(ls file.txt)
find / -samefile file.txt -print
Will find all the links to the file with the same inode number as file.txt
adding a -xdev flag will avoid find to cross device boundaries ("mount points"). (But this will probably cause nothing to be found if the find does not start at a directory on the same device as file.txt)
Do note that find can report multiple paths for a single filesystem object, because an Inode can be linked by more than one directory entry, possibly even using different names. For instance:
find /bin -samefile /bin/gunzip -ls
Will output:
12845178 4 -rwxr-xr-x 2 root root 2251 feb 9 2012 /bin/uncompress
12845178 4 -rwxr-xr-x 2 root root 2251 feb 9 2012 /bin/gunzip
Usually:
find `pwd` | grep <filename>
Alternatively, just for the current folder:
find `pwd` -maxdepth 1 | grep <filename>
This will work for both file and folder:
getAbsolutePath(){
[[ -d $1 ]] && { cd "$1"; echo "$(pwd -P)"; } ||
{ cd "$(dirname "$1")" || exit 1; echo "$(pwd -P)/$(basename "$1")"; }
}
Another Linux utility, that does this job:
fname <file>
For Mac OS, if you just want to get the path of a file in the finder, control click the file, and scroll down to "Services" at the bottom. You get many choices, including "copy path" and "copy full path". Clicking on one of these puts the path on the clipboard.
fp () {
PHYS_DIR=`pwd -P`
RESULT=$PHYS_DIR/$1
echo $RESULT | pbcopy
echo $RESULT
}
Copies the text to your clipboard and displays the text on the terminal window.
:)
(I copied some of the code from another stack overflow answer but cannot find that answer anymore)
In Mac OSX, do the following steps:
cd into the directory of the target file.
Type either of the following terminal commands.
Terminal
ls "`pwd`/file.txt"
echo $(pwd)/file.txt
Replace file.txt with your actual file name.
Press Enter
you#you:~/test$ ls
file
you#you:~/test$ path="`pwd`/`ls`"
you#you:~/test$ echo $path
/home/you/test/file
Beside "readlink -f" , another commonly used command:
$find /the/long/path/but/I/can/use/TAB/to/auto/it/to/ -name myfile
/the/long/path/but/I/can/use/TAB/to/auto/it/to/myfile
$
This also give the full path and file name at console
Off-topic: This method just gives relative links, not absolute. The readlink -f command is the right one.

Get the name of the directory where a script is executed

I have some script, that uses files in directories around it. It uses
dirname $0
command.
It should work from any directory where I run this script, but when I run a symbolic link that points to that script I get the path of symbolic link. So I get the output of dirname rather than the path of the script itself.
Any one know a way to get the path of where the script is run?
Get the real path to your script
if [ -L $0 ] ; then
ME=$(readlink $0)
else
ME=$0
fi
DIR=$(dirname $ME)
A simpler solution:
dirname $(readlink -f $0)
Tested with on Ubuntu 14.04:
which java returns /usr/bin/java, which is a symbolic link.
readlink -f `which java`
Returns /usr/lib/jvm/java-8-oracle/jre/bin/java
Finally,
dirname $(readlink -f `which java`)
Returns /usr/lib/jvm/java-8-oracle/jre/bin, which is the folder under which "java" is located.
if you have realpath installed:
$(dirname $(realpath $0))
Unless I misunderstand you, the problem should be the same as the one in: How do you normalize a file path in Bash?
An option not mentioned there is the following python one-liner:
python2.6 -c "import os,sys; print os.path.realpath(sys.argv[1])" "$0"
Finally, remember to use double quotes around "$0".

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