Bash test: get the directory of a script

unit.sh

#!/bin/bash

function test {
    MESSAGE=$1
    RECEIVED=$2
    EXPECTED=$3

    if [ "$RECEIVED" = "$EXPECTED" ]; then
        echo -e "\033[32m✔︎ Tested $MESSAGE"
    else
        echo -e "\033[31m✘ Tested $MESSAGE"
        echo -e "  Received: $RECEIVED"
        echo -e "  Expected: $EXPECTED"
    fi
    echo -en "\033[0m"
}

function testSuite {
    test 'absolute call' `bash /tmp/1234/test.sh` /tmp/1234
    test 'via symlinked dir' `bash /tmp/current/test.sh` /tmp/1234
    test 'via symlinked file' `bash /tmp/test.sh` /tmp/1234
    test 'via multiple symlinked dirs' `bash /tmp/current/loop/test.sh` /tmp/1234
    pushd /tmp >/dev/null
    test 'relative call' `bash 1234/test.sh` /tmp/1234
    popd >/dev/null
    test 'with space in dir' `bash /tmp/12\ 34/test.sh` /tmp/1234
    test 'with space in file' `bash /tmp/1234/te\ st.sh` /tmp/1234
    echo
}

function setup {
    DIR=/tmp/1234
    FILE=test.sh
    if [ -e $DIR ]; then rm -rf $DIR; fi; mkdir $DIR
    if [ -f $DIR/$FILE ]; then rm -rf $DIR/$FILE; fi; touch $DIR/$FILE
    if [ -f /tmp/$FILE ]; then rm /tmp/$FILE; fi; ln -s $DIR/$FILE /tmp
    if [ -f /tmp/current ]; then rm /tmp/current; fi; ln -s $DIR /tmp/current
    if [ -f /tmp/current/loop ]; then rm /tmp/current/loop; fi; ln -s $DIR /tmp/current/loop
    DIR2="/tmp/12 34"
    FILE2="te st.sh"
    if [ -e "$DIR2" ]; then rm -rf "$DIR2"; fi; mkdir "$DIR2"
    if [ -f "$DIR/$FILE2" ]; then rm -rf "$DIR/$FILE2"; fi; ln -s $DIR/$FILE "$DIR/$FILE2"
    if [ -f "$DIR2/$FILE" ]; then rm -rf "$DIR2/$FILE"; fi; ln -s $DIR/$FILE "$DIR2/$FILE"
    if [ -f "$DIR2/$FILE2" ]; then rm -rf "$DIR2/$FILE2"; fi; ln -s $DIR/$FILE "$DIR2/$FILE2"
}

function test1 {
    echo 'Test 1: via dirname'
    cat <<- EOF >/tmp/1234/test.sh
	echo \`dirname \$0\`
	EOF
    testSuite
}

function test2 {
    echo 'Test 2: via pwd'
    cat <<- EOF >/tmp/1234/test.sh
	CACHE_DIR=\$( cd "\$( dirname "\${BASH_SOURCE[0]}" )" && pwd )
	echo \$CACHE_DIR
	EOF
    testSuite
}

function test3 {
    echo 'Test 3: overcomplicated stackoverflow solution'
    cat <<- EOF >/tmp/1234/test.sh
	SOURCE="\${BASH_SOURCE[0]}"
	while [ -h "\$SOURCE" ]; do
	  DIR="\$( cd -P "\$( dirname "\$SOURCE" )" && pwd )"
	  SOURCE="\$(readlink "\$SOURCE")"
	  [[ \$SOURCE != /* ]] && SOURCE="\$DIR/\$SOURCE"
	done
	DIR="\$( cd -P "\$( dirname "\$SOURCE" )" && pwd )"
	echo \$DIR
	EOF
    testSuite
}

function test4 {
    echo 'Test 4: via readlink'
    cat <<- EOF >/tmp/1234/test.sh
	echo \`dirname \$(readlink -f \$0)\`
	EOF
    testSuite
}

function test5 {
    echo 'Test 5: via readlink with space'
    cat <<- EOF >/tmp/1234/test.sh
	echo \`dirname \$(readlink -f "\$0")\`
	EOF
    testSuite
}
echo
setup
if [ "$1" != "" ]; then
    $1
else
    test1
    test2
    test3
    test4
    test5
fi

[tvl@yoga /tmp]
$ bash unit.sh 

Test 1: via dirname
✔︎ Tested absolute call
✘ Tested via symlinked dir
  Received: /tmp/current
  Expected: /tmp/1234
✘ Tested via symlinked file
  Received: /tmp
  Expected: /tmp/1234
✘ Tested via multiple symlinked dirs
  Received: /tmp/current/loop
  Expected: /tmp/1234
✘ Tested relative call
  Received: 1234
  Expected: /tmp/1234
✘ Tested with space in dir
  Received: /tmp
  Expected: 34
✘ Tested with space in file
  Received: /tmp/1234
  Expected: .

Test 2: via pwd
✔︎ Tested absolute call
✘ Tested via symlinked dir
  Received: /tmp/current
  Expected: /tmp/1234
✘ Tested via symlinked file
  Received: /tmp
  Expected: /tmp/1234
✘ Tested via multiple symlinked dirs
  Received: /tmp/current/loop
  Expected: /tmp/1234
✔︎ Tested relative call
✘ Tested with space in dir
  Received: /tmp/12
  Expected: 34
✔︎ Tested with space in file

Test 3: overcomplicated stackoverflow solution
✔︎ Tested absolute call
✔︎ Tested via symlinked dir
✔︎ Tested via symlinked file
✔︎ Tested via multiple symlinked dirs
✔︎ Tested relative call
✔︎ Tested with space in dir
✔︎ Tested with space in file

Test 4: via readlink
✔︎ Tested absolute call
✔︎ Tested via symlinked dir
✔︎ Tested via symlinked file
✔︎ Tested via multiple symlinked dirs
✔︎ Tested relative call
✘ Tested with space in dir
  Received: /tmp
  Expected: /tmp/1234
✘ Tested with space in file
  Received: /tmp/1234
  Expected: /home/tvl/Desktop

Test 5: via readlink with space
✔︎ Tested absolute call
✔︎ Tested via symlinked dir
✔︎ Tested via symlinked file
✔︎ Tested via multiple symlinked dirs
✔︎ Tested relative call
✔︎ Tested with space in dir
✔︎ Tested with space in file

Test 4 doesn't work on Mac OS X because readlink behaves differently there (no -f option). That's why the solution from test 3 is preferable

Thanks for the feedback. I didn't check on a Mac.
You can get the readline behaviour of GNU on Mac like this:

brew install coreutils
alias readlink=greadlink

@tvlooy I don't want to force the end user to install coreutils on her/his Mac. I agree with udalov. However, the test 3 doesn't work under Ubuntu when called in a desktop file when clicking on the icon of the application.

maybe because of tests 6 and 7 that I added, I updated the script

For OS X: TEST 3 as a ready-to-use function.

# TEST 3
# http://stackoverflow.com/a/246128
# https://gist.github.com/tvlooy/cbfbdb111a4ebad8b93e
function abs_script_dir_path {
    SOURCE=${BASH_SOURCE[0]}
    while [ -h "$SOURCE" ]; do
      DIR=$( cd -P $( dirname "$SOURCE") && pwd )
      SOURCE=$(readlink "$SOURCE")
      [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE"
    done
    DIR=$( cd -P $( dirname "$SOURCE" ) && pwd )
    echo $DIR
}

So that you can correctly get the directory when running source dir/to/script.sh in Bash and ZSH:

function abs_script_dir_path {
    SOURCE=$(if [ -z "${BASH_SOURCE[0]}"]; then echo $1; else echo ${BASH_SOURCE[0]}; fi)
    while [ -h "$SOURCE" ]; do
      DIR=$( cd -P $( dirname "$SOURCE") && pwd )
      SOURCE=$(readlink "$SOURCE")
      [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE"
    done
    DIR=$( cd -P $( dirname "$SOURCE" ) && pwd )
    echo $DIR
}

DIR=$(abs_script_dir_path $0)

@tvlooy, I don't have readlink in my system (AIX 7.1) but the following seems to pass all test scenarios:

#!/usr/bin/bash
__SOURCE__="\${BASH_SOURCE[0]}"
while [[ -h "\${__SOURCE__}" ]]; do
    __SOURCE__=\$(find "\${__SOURCE__}" -type l -ls | sed -n 's/^.* -> \(.*\)/\1/p');
done;

echo \$( cd -P "\$( dirname "\${__SOURCE__}" )" && pwd )

I'm using the fact find -ls is returning the string:

lrwxrwxrwx    1 <user> <group> <timestamp>  <symlink> -> <symlinked source>

so sed should be able to handle this (I even tried using filenames with " -> ").

I should note that my test results are different:

Test 1: via dirname
✔︎ Tested absolute call
✘ Tested via symlinked dir
  Received: /tmp/current
  Expected: /tmp/1234
✘ Tested via symlinked file
  Received: /tmp
  Expected: /tmp/1234
✘ Tested via multiple symlinked dirs
  Received: /tmp/current/loop
  Expected: /tmp/1234
✘ Tested relative call
  Received: 1234
  Expected: /tmp/1234
✘ Tested with space in dir
  Received: /tmp/12 34
  Expected: /tmp/1234
✔︎ Tested with space in file

Test 2: via pwd
✔︎ Tested absolute call
✘ Tested via symlinked dir
  Received: /tmp/current
  Expected: /tmp/1234
✘ Tested via symlinked file
  Received: /tmp
  Expected: /tmp/1234
✘ Tested via multiple symlinked dirs
  Received: /tmp/current/loop
  Expected: /tmp/1234
✔︎ Tested relative call
✘ Tested with space in dir
  Received: /tmp/12 34
  Expected: /tmp/1234
✔︎ Tested with space in file

Test 3: overcomplicated stackoverflow solution
✔︎ Tested absolute call
✔︎ Tested via symlinked dir
✘ Tested via symlinked file
  Received:
  Expected: /tmp/1234
✔︎ Tested via multiple symlinked dirs
✔︎ Tested relative call
✘ Tested with space in dir
  Received:
  Expected: /tmp/1234
✘ Tested with space in file
  Received:
  Expected: /tmp/1234

Test 4: via readlink
✘ Tested absolute call
  Received: .
  Expected: /tmp/1234
✘ Tested via symlinked dir
  Received: .
  Expected: /tmp/1234
✘ Tested via symlinked file
  Received: .
  Expected: /tmp/1234
✘ Tested via multiple symlinked dirs
  Received: .
  Expected: /tmp/1234
✘ Tested relative call
  Received: .
  Expected: /tmp/1234
✘ Tested with space in dir
  Received: .
  Expected: /tmp/1234
✘ Tested with space in file
  Received: .
  Expected: /tmp/1234

Test 5: via readlink with space
✘ Tested absolute call
  Received: .
  Expected: /tmp/1234
✘ Tested via symlinked dir
  Received: .
  Expected: /tmp/1234
✘ Tested via symlinked file
  Received: .
  Expected: /tmp/1234
✘ Tested via multiple symlinked dirs
  Received: .
  Expected: /tmp/1234
✘ Tested relative call
  Received: .
  Expected: /tmp/1234
✘ Tested with space in dir
  Received: .
  Expected: /tmp/1234
✘ Tested with space in file
  Received: .
  Expected: /tmp/1234

Test 6: as Test 2 but with cd -P
✔︎ Tested absolute call
✔︎ Tested via symlinked dir
✘ Tested via symlinked file
  Received: /tmp
  Expected: /tmp/1234
✔︎ Tested via multiple symlinked dirs
✔︎ Tested relative call
✘ Tested with space in dir
  Received: /tmp/12 34
  Expected: /tmp/1234
✔︎ Tested with space in file

Test 7: via cd -P and pwd, testing for symlinked file first
✔︎ Tested absolute call
✔︎ Tested via symlinked dir
✔︎ Tested via symlinked file
✔︎ Tested via multiple symlinked dirs
✔︎ Tested relative call
✔︎ Tested with space in dir
✔︎ Tested with space in file

My code is test 7
I add some guards on tests 3, 4 and 5 so I wouldn't get any errors.

If you want, you can merge my fork from https://gist.github.com/gvlx/0adfb1137937ad443df2eeaa73dc0ba7/44efc8c3b18e9dc3495afa7358be3ea0aa53365f .

No portable POSIX version here. This should do:

function test6 {
    echo 'Test 6: posix compliant'
    cat <<- EOF >/tmp/1234/test.sh
	SOURCE="\$0"

	script_dir() {
		mysource=\${SOURCE}

		while [ -h "\${mysource}" ]; do
			DIR="\$( cd -P "\$( dirname "\${mysource}" )" > /dev/null && pwd )"
			mysource="\$(readlink "\${mysource}")"
			[ "\${mysource%\${mysource#?}}"x != '/x' ] && mysource="\${DIR}/\${mysource}"
		done
		DIR="\$( cd -P "\$( dirname "\${mysource}" )" > /dev/null && pwd )"
		echo "\${DIR}"

		unset mysource DIR
	}
	echo \$(script_dir)
	EOF
    testSuite
}

greadlink -f unfortunately doesn't work effectively when sourceing the script on Mac :(

New fork https://gist.github.com/ptc-mrucci/61772387878ed53a6c717d51a21d9371 includes:

• @glvx changes
• macOS support
• new python-based implementation (motivation: https://stackoverflow.com/a/68056148/133106)
• improved quoting