Question

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 

Answer 1

#!/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'