Getting the source directory of a Bash script from

Question

How do I get the path of the directory in which a Bash script is located, inside that script?

For instance, let's say 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

None of these worked for a bash script launched by Finder in OS X - I ended up using:

SCRIPT_LOC="`ps -p $$ | sed /PID/d | sed s:.*/Network/:/Network/: |
sed s:.*/Volumes/:/Volumes/:`"

Not pretty, but it gets the job done.

Answer 2

#!/bin/sh
PRG="$0"

# need this for relative symlinks
while [ -h "$PRG" ] ; do
   PRG=`readlink "$PRG"`
done

scriptdir=`dirname "$PRG"`

Answer 3

So... I believe I've got this one. Late to the party, but I think some will appreciate it being here is them 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

Answer 4

The best compact solution in my view would be:

"$( cd "$( echo "${BASH_SOURCE[0]%/*}" )"; pwd )"

There is no reliance on anything other than Bash. The use of dirname, readlink and basename will eventually lead to compatibility issues, so they are best avoided if at all possible.

Answer 5

SCRIPT_DIR=$( cd ${0%/*} && pwd -P )

Answer 6

I am tired of coming to this page over and over to copy paste the one-liner in the accepted answer. The problem with that is it is not easy to understand and remember.

Here is an easy-to-remember script:

DIR=$(dirname "${BASH_SOURCE[0]}")  # get the directory name
DIR=$(realpath "${DIR}")    # resolve its full path if need be