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
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
source" aka . (dot) operator.$0 is modified from caller."./script""/full/path/to/script""/some/path/../../another/path/script""./some/folder/script"Alternatively, if the Bash script itself is a relative symlink you want to follow it and return the full path of the linked-to script:
pushd . > '/dev/null';
SCRIPT_PATH="${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 -f -- "$DIR"; )"; # Resolve its full path if need be
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.
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 "$0")"; pwd)
The shortest and most elegant way to do this is:
#!/bin/bash
DIRECTORY=$(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?".
#!/bin/sh
PRG="$0"
# need this for relative symlinks
while [ -h "$PRG" ] ; do
PRG=`readlink "$PRG"`
done
scriptdir=`dirname "$PRG"`
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")"
...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 "${BASH_SOURCE[-1]}", however, gave me what I did not want: the expanded path to ~/.bashrc.
Example command and output:
~/GS/dev/eRCaGuy_hello_world/bash$ ./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"
. 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 "${BASH_SOURCE[-1]}")"
This way, symbolic links are NOT expanded. Rather, they are left as-is, as symbolic links in the full path.
The code above is now part of my eRCaGuy_hello_world repo in this file here: bash/get_script_path.sh. Reference and run this file for full examples both with and withOUT symlinks in the paths. See the bottom of the file for example output in both cases.
BASH_SOURCE variable: Unix & Linux: determining path to sourced shell scriptBASH_SOURCE is actually an array, and we want the last element from it for it to work as expected inside a function (hence why I used "${BASH_SOURCE[-1]}" in my code here): Unix & Linux: determining path to sourced shell scriptman bash --> search for BASH_SOURCE:
BASH_SOURCEAn array variable whose members are the source filenames where the corresponding shell function names in the
FUNCNAMEarray variable are defined. The shell function${FUNCNAME[$i]}is defined in the file${BASH_SOURCE[$i]}and called from${BASH_SOURCE[$i+1]}.
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 "$0" )" )/lib/B"
It doesn't matter where the user is or how he/she calls the script. This will always work.
Try the following cross-compatible solution:
CWD="$(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:
Hmm, if in the path, basename and dirname are just not going to cut it and walking the path is hard (what if the parent didn't export PATH?!).
However, the shell has to have an open handle to its script, and in Bash the handle is #255.
SELF=`readlink /proc/$$/fd/255`
works for me.
You can do that just combining the script name ($0) with realpath and/or dirname. It works for Bash and Shell.
#!/usr/bin/env bash
RELATIVE_PATH="${0}"
RELATIVE_DIR_PATH="$(dirname "${0}")"
FULL_DIR_PATH="$(realpath "${0}" | xargs dirname)"
FULL_PATH="$(realpath "${0}")"
echo "RELATIVE_PATH->${RELATIVE_PATH}<-"
echo "RELATIVE_DIR_PATH->${RELATIVE_DIR_PATH}<-"
echo "FULL_DIR_PATH->${FULL_DIR_PATH}<-"
echo "FULL_PATH->${FULL_PATH}<-"
The output will be something like this:
# RELATIVE_PATH->./bin/startup.sh<-
# RELATIVE_DIR_PATH->./bin<-
# FULL_DIR_PATH->/opt/my_app/bin<-
# FULL_PATH->/opt/my_app/bin/startup.sh<-
$0 is the name of the script itself
An example: LozanoMatheus/get_script_paths.sh
This is, annoyingly, the only one-liner I've found that works on both Linux and macOS when the executable script is a symlink:
SCRIPT_DIR=$(python -c "import os; print(os.path.dirname(os.path.realpath('${BASH_SOURCE[0]}')))")
or, similarly, using python3 pathlib module:
SCRIPT_DIR=$(python3 -c "from pathlib import Path; print(Path('${BASH_SOURCE[0]}').resolve().parent)")
Tested on Linux and macOS and compared to other solutions in this gist: https://gist.github.com/ptc-mrucci/61772387878ed53a6c717d51a21d9371
The top response does not work in all cases...
As I had problems with the BASH_SOURCE with the included 'cd' approach on some very fresh and also on less fresh installed Ubuntu 16.04 (Xenial Xerus) systems when invoking the shell script by means of "sh my_script.sh", I tried out something different that as of now seems to run quite smoothly for my purposes. The approach is a bit more compact in the script and is further much lesser cryptic feeling.
This alternate approach uses the external applications 'realpath' and 'dirname' from the coreutils package. (Okay, not anyone likes the overhead of invoking secondary processes - but when seeing the multi-line scripting for resolving the true object it won't be that bad either having it solve in a single binary usage.)
So let’s see one example of those alternate solution for the described task of querying the true absolute path to a certain file:
PATH_TO_SCRIPT=`realpath -s $0`
PATH_TO_SCRIPT_DIR=`dirname $PATH_TO_SCRIPT`
But preferably you should use this evolved version to also support the use of paths with spaces (or maybe even some other special characters):
PATH_TO_SCRIPT=`realpath -s "$0"`
PATH_TO_SCRIPT_DIR=`dirname "$PATH_TO_SCRIPT"`
Indeed, if you don’t need the value of the SCRIPT variable then you might be able to merge this two-liner into even a single line. But why really shall you spend the effort for this?
None of the current solutions work if there are any newlines at the end of the directory name - They will be stripped by the command substitution. To work around this you can append a non-newline character inside the command substitution and then strip just that character off:
dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd && echo x)"
dir="${dir%x}"
This protects against two very common situations: Accidents and sabotage. A script shouldn't fail in unpredictable ways just because someone, somewhere, did a mkdir $'\n'.
This is the only way I've found to tell reliably:
SCRIPT_DIR=$(dirname $(cd "$(dirname "$BASH_SOURCE")"; pwd))
Here's a command that works under either Bash or zsh, and whether executed stand-alone or sourced:
[ -n "$ZSH_VERSION" ] && this_dir=$(dirname "${(%):-%x}") \
|| this_dir=$(dirname "${BASH_SOURCE[0]:-$0}")
${(%):-%x}${(%):-%x} in zsh expands to the path of the currently-executing file.
:-You know already that ${...} substitutes variables inside of strings. You might not know that certain operations are possible (in both Bash and zsh) on the variables during substitution, like the fallback expansion operator :-:
% x=ok
% echo "${x}"
ok
% echo "${x:-fallback}"
ok
% x=
% echo "${x:-fallback}"
fallback
% y=yvalue
% echo "${x:-$y}"
yvalue
%x prompt escape codeNext, we'll introduce prompt escape codes, a zsh-only feature. In zsh, %x will expand to the path of the file, but normally this is only when doing expansion for prompt strings. To enable those codes in our substitution, we can add a (%) flag before the variable name:
% cat apath/test.sh
fpath=%x
echo "${(%)fpath}"
% source apath/test.sh
apath/test.sh
% cd apath
% source test.sh
test.sh
What we have so far works, but it would be tidier to avoid creating the extra fpath variable. Instead of putting %x in fpath, we can use :- and put %x in the fallback string:
% cat test.sh
echo "${(%):-%x}"
% source test.sh
test.sh
Note that we normally would put a variable name between (%) and :-, but we left it blank. The variable with a blank name can't be declared or set, so the fallback is always triggered.
print -P %x?Now we almost have the directory of our script. We could have used print -P %x to get the same file path with fewer hacks, but in our case, where we need to pass it as an argument to dirname, that would have required the overhead of a starting a new subshell:
% cat apath/test.sh
dirname "$(print -P %x)" # $(...) runs a command in a new process
dirname "${(%):-%x}"
% source apath/test.sh
apath
apath
It turns out that the hacky way is both more performant and succinct.
One advantage of this method is that it doesn't involve anything outside Bash itself and does not fork any subshell neither.
First, use pattern substitution to replace anything not starting with / (i.e., a relative path) with $PWD/. Since we use a substitution to match the first character of $0, we also have to append it back (${0:0:1} in the substitution).
Now we have a full path to the script; we can get the directory by removing the last / and anything the follows (i.e., the script name). That directory can then be used in cd or as a prefix to other paths relative to your script.
#!/bin/bash
BIN=${0/#[!\/]/"$PWD/${0:0:1}"}
DIR=${BIN%/*}
cd "$DIR"
If your script may be sourced rather than executed, you can of course replace $0 with ${BASH_SOURCE[0]}, such as:
BIN=${BASH_SOURCE[0]/#[!\/]/"$PWD/${BASH_SOURCE[0]:0:1}"}
This will work for executable scripts too. It's longer, but more polyvalent.
If your Bash script is a symlink, then this is the way to do it:
#!/usr/bin/env bash
dirn="$(dirname "$0")"
rl="$(readlink "$0")";
exec_dir="$(dirname $(dirname "$rl"))";
my_path="$dirn/$exec_dir";
X="$(cd $(dirname ${my_path}) && pwd)/$(basename ${my_path})"
X is the directory that contains your Bash script (the original file, not the symlink). I swear to God this works, and it is the only way I know of doing this properly.
/tmp/a/b/c $ . ./test.sh
/tmp/a/b/c
/tmp/a/b/c $ . /tmp/a/b/c/test.sh
/tmp/a/b/c
/tmp/a/b/c $ ./test.sh
/tmp/a/b/c
/tmp/a/b/c $ /tmp/a/b/c/test.sh
/tmp/a/b/c
/tmp/a/b/c $ cd
~ $ . /tmp/a/b/c/test.sh
/tmp/a/b/c
~ $ . ../../tmp/a/b/c/test.sh
/tmp/a/b/c
~ $ /tmp/a/b/c/test.sh
/tmp/a/b/c
~ $ ../../tmp/a/b/c/test.sh
/tmp/a/b/c
#!/usr/bin/env bash
# snagged from: https://stackoverflow.com/a/51264222/26510
function toAbsPath {
local target
target="$1"
if [ "$target" == "." ]; then
echo "$(pwd)"
elif [ "$target" == ".." ]; then
echo "$(dirname "$(pwd)")"
else
echo "$(cd "$(dirname "$1")"; pwd)/$(basename "$1")"
fi
}
function getScriptDir(){
local SOURCED
local RESULT
(return 0 2>/dev/null) && SOURCED=1 || SOURCED=0
if [ "$SOURCED" == "1" ]
then
RESULT=$(dirname "$1")
else
RESULT="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
fi
toAbsPath "$RESULT"
}
SCRIPT_DIR=$(getScriptDir "$0")
echo "$SCRIPT_DIR"
Python was mentioned a few times. Here is the JavaScript (i.e., Node.js) alternative:
baseDirRelative=$(dirname "$0")
baseDir=$(node -e "console.log(require('path').resolve('$baseDirRelative'))") # Get absolute path using Node.js
echo $baseDir
I tried the followings with 3 different executions.
echo $(realpath $_). application # /correct/path/to/dir or /path/to/temporary_dir
bash application # /path/to/bash
/PATH/TO/application # /correct/path/to/dir
echo $(realpath $(dirname $0)). application # failed with `realpath: missing operand`
bash application # /correct/path/to/dir
/PATH/TO/application # /correct/path/to/dir
echo $(realpath $BASH_SOURCE)$BASH_SOURCE is basically the same with ${BASH_SOURCE[0]}.
. application # /correct/path/to/dir
bash application # /correct/path/to/dir
/PATH/TO/application # /correct/path/to/dir
Only $(realpath $BASH_SOURCE) seems to be reliable.
Most answers either don't handle files which are symlinked via a relative path, aren't one-liners or don't handle BSD (Mac). A solution which does all three is:
HERE=$(cd "$(dirname "$BASH_SOURCE")"; cd -P "$(dirname "$(readlink "$BASH_SOURCE" || echo .)")"; pwd)
First, cd to bash's conception of the script's directory. Then readlink the file to see if it is a symlink (relative or otherwise), and if so, cd to that directory. If not, cd to the current directory (necessary to keep things a one-liner). Then echo the current directory via pwd.
You could add -- to the arguments of cd and readlink to avoid issues of directories named like options, but I don't bother for most purposes.
You can see the full explanation with illustrations here:
https://www.binaryphile.com/bash/2020/01/12/determining-the-location-of-your-script-in-bash.html
I usually do:
LIBDIR=$(dirname "$(readlink -f "$(type -P $0 || echo $0)")")
source $LIBDIR/lib.sh
Here's an excerpt from my answer to shell script: check directory name and convert to lowercase in which I demonstrate not only how to solve this problem with very basic POSIX-specified utilities, I also address how to very simply store the function's results in a returned variable...
...Well, as you can see, with some help, I hit upon a pretty simple and very powerful solution:
I can pass the function a sort of messenger variable and dereference any explicit use of the resulting function's argument's $1 name with eval as necessary, and, upon the function routine's completion, I use eval and a backslashed quoting trick to assign my messenger variable the value I desire without ever having to know its name.
In full disclosure, ... (I found the messenger variable portion of this) and at Rich's sh tricks and I have also excerpted the relevant portion of his page below my own answer's excerpt.
... EXCERPT: ...
Though not strictly POSIX yet, realpath is a GNU core application since 2012. Full disclosure: never heard of it before I noticed it in the info coreutils TOC and immediately thought of [the linked] question, but using the following function as demonstrated should reliably, (soon POSIXLY?), and, I hope, efficiently
provide its caller with an absolutely sourced $0:
% _abs_0() {
> o1="${1%%/*}"; ${o1:="${1}"}; ${o1:=`realpath -s "${1}"`}; eval "$1=\${o1}";
> }
% _abs_0 ${abs0:="${0}"} ; printf %s\\n "${abs0}"
/no/more/dots/in/your/path2.sh
It may be worth highlighting that this solution uses POSIX parameter expansion to first check if the path actually needs expanding and resolving at all before attempting to do so. This should return an absolutely sourced $0via a messenger variable (with the notable exception that it will preserve symlinks) as efficiently as I could imagine it could be done whether or not the path is already absolute.
...
(minor edit: before finding realpath in the docs, I had at least pared down my version of (the version below) not to depend on the time field (as it does in the first ps command), but, fair warning, after testing some I'm less convinced ps is fully reliable in its command path expansion capacity)
On the other hand, you could do this:
ps ww -fp $$ | grep -Eo '/[^:]*'"${0#*/}"
eval "abs0=${`ps ww -fp $$ | grep -Eo ' /'`#?}"
... And from Rich's sh tricks: ...
Returning strings from a shell function
As can be seen from the above pitfall of command substitution, standard output is not a good avenue for shell functions to return strings to their caller, unless the output is in a format where trailing newlines are insignificant. Certainly such practice is not acceptable for functions meant to deal with arbitrary strings. So, what can be done?
Try this:
func () {
body here
eval "$1=\${foo}"
}
Of course, ${foo} could be replaced by any sort of substitution. The key trick here is the eval line and the use of escaping. The “$1” is expanded when the argument to eval is constructed by the main command parser. But the “${foo}” is not expanded at this stage, because the “$” has been quoted. Instead, it’s expanded when eval evaluates its argument. If it’s not clear why this is important, consider how the following would be bad:
foo='hello ; rm -rf /'
dest=bar
eval "$dest=$foo"
But of course the following version is perfectly safe:
foo='hello ; rm -rf /'
dest=bar
eval "$dest=\$foo"
Note that in the original example, “$1” was used to allow the caller to pass the destination variable name as an argument the function. If your function needs to use the shift command, for instance to handle the remaining arguments as “$@”, then it may be useful to save the value of “$1” in a temporary variable at the beginning of the function.
The below stores the script's directory path in the dir variable.
(It also tries to support being executed under Cygwin in Windows.)
And at last it runs the my-sample-app executable with all arguments passed to this script using "$@":
#!/usr/bin/env sh
dir=$(cd "${0%[/\\]*}" > /dev/null && pwd)
if [ -d /proc/cygdrive ]; then
case "$(uname -s)" in
CYGWIN*|MINGW32*|MSYS*|MINGW*)
# We are under Windows, so translate path to Windows format.
dir=$(cygpath -m "$dir");
;;
esac
fi
# Runs the executable which is beside this script
"${dir}/my-sample-app" "$@"
I think the simplest answer is a parameter expansion of the original variable:
#!/usr/bin/env bash
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
echo "opt1; original answer: $DIR"
echo ''
echo "opt2; simple answer : ${BASH_SOURCE[0]%/*}"
It should produce output like:
$ /var/tmp/test.sh
opt1; original answer: /var/tmp
opt2; simple answer : /var/tmp
The variable/parameter expansion ${BASH_SOURCE[0]%/*}" seems much easier to maintain.
If not sourced by parent script and not symlinked, $0 is enough:
script_path="$0"
If sourced by parent script and not symlinked, use $BASH_SOURCE or ${BASH_SOURCE[0]}:
script_path="$BASH_SOURCE"
If symlinked, use $BASH_SOURCE with realpath or readlink -f to get the real file path:
script_path="$(realpath "$BASH_SOURCE")"
In addition, realpath or readlink -f returns the absolute path.
To get the directory of the script, use dirname:
script_directory="$(dirname "$script_path")"
realpath or readlink -f here or here.${var-string} parameter expansion. Example: Make it compatible with Zsh.You can get the source directory of a Bash script from within the script itself on follow short way:
script_path=$(dirname "$(readlink -f "$0")")"/"
echo "$script_path"
Sample output:
/home/username/desktop/
Based on this answer, I suggest the clarified version that gets SCRIPT_HOME as the containing folder of any currently-running Bash script:
s=${BASH_SOURCE[0]} ; s=`dirname $s` ; SCRIPT_HOME=`cd $s ; pwd`
echo $SCRIPT_HOME
I want to comment on the previous answer up there (How can I get the source directory of a Bash script from within the script itself?), but don't have enough reputation to do that.
I found a solution for this two years ago on Apple's documentation site: https://developer.apple.com/library/archive/documentation/OpenSource/Conceptual/ShellScripting/AdvancedTechniques/AdvancedTechniques.html. And I stuck to this method afterwards. It cannot handle soft link, but otherwise works pretty well for me. I'm posting it here for any who needs it and as a request for comment.
#!/bin/sh
# Get an absolute path for the poem.txt file.
POEM="$PWD/../poem.txt"
# Get an absolute path for the script file.
SCRIPT="$(which $0)"
if [ "x$(echo $SCRIPT | grep '^\/')" = "x" ] ; then
SCRIPT="$PWD/$SCRIPT"
fi
As shown by the code, after you get the absolute path of the script, then you can use the dirname command to get the path of the directory.
I want to make sure that the script is running in its directory. So
cd $(dirname $(which $0) )
After this, if you really want to know where the you are running then run the command below.
DIR=$(/usr/bin/pwd)
There is no 100% portable and reliable way to request a path to a current script directory. Especially between different backends like Cygwin, MinGW, MSYS, Linux, etc. This issue was not properly and completely resolved in Bash for ages.
For example, this could not be resolved if you want to request the path after the source command to make nested inclusion of another Bash script which is in turn use the same source command to include another Bash script and so on.
In case of the source command, I suggest to replace the source command with something like this:
function include()
{
if [[ -n "$CURRENT_SCRIPT_DIR" ]]; then
local dir_path=... get directory from `CURRENT_SCRIPT_DIR/$1`, depends if $1 is absolute path or relative ...
local include_file_path=...
else
local dir_path=... request the directory from the "$1" argument using one of answered here methods...
local include_file_path=...
fi
... push $CURRENT_SCRIPT_DIR in to stack ...
export CURRENT_SCRIPT_DIR=... export current script directory using $dir_path ...
source "$include_file_path"
... pop $CURRENT_SCRIPT_DIR from stack ...
}
From now on, the use of include(...) is based on previous CURRENT_SCRIPT_DIR in your script.
This only works when you can replace all source commands by include command. If you can't, then you have no choice. At least until developers of the Bash interpreter make an explicit command to request the current running script directory path.
My own closest implementation to this:
https://sourceforge.net/p/tacklelib/tacklelib/HEAD/tree/trunk/bash/tacklelib/bash_tacklelib
https://github.com/andry81/tacklelib/tree/trunk/bash/tacklelib/bash_tacklelib
(search for the tkl_include function)
This is what I crafted throughout the years to use as a header on my Bash scripts:
## BASE BRAIN - Get where you're from and who you are.
MYPID=$$
ORIGINAL_DIR="$(pwd)" # This is not a hot air balloon ride..
fa="$0" # First Assumption
ta= # Temporary Assumption
wa= # Weighed Assumption
while true; do
[ "${fa:0:1}" = "/" ] && wa=$0 && break
[ "${fa:0:2}" = "./" ] && ta="${ORIGINAL_DIR}/${fa:2}" && [ -e "$ta" ] && wa="$ta" && break
ta="${ORIGINAL_DIR}/${fa}" && [ -e "$ta" ] && wa="$ta" && break
done
SW="$wa"
SWDIR="$(dirname "$wa")"
SWBIN="$(basename "$wa")"
unset ta fa wa
( [ ! -e "$SWDIR/$SWBIN" ] || [ -z "$SW" ] ) && echo "I could not find my way around :( possible bug in the TOP script" && exit 1
At this point, your variables SW, SWDIR, and SWBIN contain what you need.
The chosen answer works very well. I'm posting my solution for anyone looking for shorter alternatives that still addresses sourcing, executing, full paths, relative paths, and symlinks. Finally, this will work on macOS, given that it cannot be assumed that GNU's coreutils' version of readlink is available.
The gotcha is that it's not using Bash, but it is easy to use in a Bash script. While the OP did not place any constraints on the language of the solution, it's probably best that most have stayed within the Bash world. This is just an alternative, and possibly an unpopular one.
PHP is available on macOS by default, and installed on a number of other platforms, though not necessarily by default. I realize this is a shortcoming, but I'll leave this here for any people coming from search engines, anyway.
export SOURCE_DIRECTORY="$(php -r 'echo dirname(realpath($argv[1]));' -- "${BASH_SOURCE[0]}")"