How can I get the source directory of a Bash script from within the script itself?

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Top 5 Answer for How can I get the source directory of a Bash script from within the script itself?

vote vote

98

#!/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=${BASH_SOURCE[0]} while [ -h "$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=${BASH_SOURCE[0]} while [ -h "$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' 
vote vote

82

Use dirname "$0":

#!/bin/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 
vote vote

75

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:

#!/bin/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 
vote vote

69

pushd . > /dev/null SCRIPT_PATH="${BASH_SOURCE[0]}" if ([ -h "${SCRIPT_PATH}" ]); then   while([ -h "${SCRIPT_PATH}" ]); do cd "$(dirname "$SCRIPT_PATH")";   SCRIPT_PATH=$(readlink "${SCRIPT_PATH}"); done fi cd "$(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="${BASH_SOURCE[0]}"; if ([ -h "${SCRIPT_PATH}" ]) then   while([ -h "${SCRIPT_PATH}" ]) do cd "$(dirname "$SCRIPT_PATH")"; SCRIPT_PATH=`readlink "${SCRIPT_PATH}"`; done fi 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.

vote vote

50

You can use $BASH_SOURCE:

#!/bin/bash  scriptdir=$(dirname "$BASH_SOURCE") 

Note that you need to use #!/bin/bash and not #!/bin/sh since it's a Bash extension.

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