Related
This is a part of a bash script.
DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
source $DIR/framework.sh $#
Please someone explain what these two lines mean.. It looks like it's going to the directory where ${BASH_SOURCE[0]} exists and assigning pwd result to DIR, but I can't first understand the syntax ${BASH_SOURCE[0]}. Is there variable array in bash? and the second one is why doesn't it just do
DIR=$( $( dirname "${BASH_SOURCE[0]}" )" )
?
The first line gives the absolute path to the script, rather than a relative path. A relative path would be something like somedir/myscript.sh, where you don't know exactly where somedir is. An absolute path would be something like /home/seumasmac/somedir/myscript.sh, where we know exactly where on the filesystem the script is.
${BASH_SOURCE[0]} contains the path used to call the script. So, it might return something like somedir/myscript.sh. It's similar to $0, the main difference being that it also works when a script is sourced rather than directly invoked.
If you did dirname somedir/myscript.sh it would just return somedir. So, instead the script does a cd into somedir and then it runs pwd. That gives the full absolute path to the directory.
The second line includes framework.sh from the same directory, using the source command.
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
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:
#!/usr/bin/env 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
$0: ./whatdirlink.sh
basename: whatdirlink.sh
dirname: .
dirname/readlink: /Users/phatblat
There is however one case where this doesn't work, when the script is sourced (instead of executed) in bash:
>>>$ cd /tmp
>>>$ . ~/whatdir.sh
pwd: /tmp
$0: bash
basename: bash
dirname: .
dirname/readlink: /tmp
pushd . > '/dev/null';
SCRIPT_PATH="${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
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]:-$0}";
while [ -h "$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 -e -- "$DIR"; )"; # Resolve its full path if need be
Short answer:
"`dirname -- "$0";`"
or (preferably):
"$( dirname -- "$0"; )"
This should do it:
DIR="$(dirname "$(realpath "$0")")"
This works with symlinks and spaces in path.
Please see the man pages for dirname and realpath.
Please add a comment on how to support MacOS. I'm sorry I can verify it.
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 -- "$0"; )";
solves the specific scenario in the question, I find having the absolute path to more more useful generally.
SCRIPT_DIR=$( cd ${0%/*} && pwd -P )
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)
$(dirname "$(readlink -f "$BASH_SOURCE")")
This is Linux specific, but you could use:
SELF=$(readlink /proc/$$/fd/255)
Here is a POSIX compliant one-liner:
SCRIPT_PATH=`dirname "$0"`; SCRIPT_PATH=`eval "cd \"$SCRIPT_PATH\" && pwd"`
# test
echo $SCRIPT_PATH
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?".
Summary:
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")"
Details:
How to obtain the full file path, full directory, and base filename of any script being run OR sourced...
...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:
Running the script:
~/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"
Sourcing the script with . 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.
References:
How to retrieve absolute path given relative
taught me about the BASH_SOURCE variable: Unix & Linux: determining path to sourced shell script
taught me that BASH_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 script
man bash --> search for BASH_SOURCE:
BASH_SOURCE
An array variable whose members are the source filenames where the corresponding shell function names in the FUNCNAME array variable are defined. The shell function ${FUNCNAME[$i]} is defined in the file ${BASH_SOURCE[$i]} and called from ${BASH_SOURCE[$i+1]}.
See also:
[my answer] Unix & Linux: determining path to sourced shell script
#!/bin/sh
PRG="$0"
# need this for relative symlinks
while [ -h "$PRG" ] ; do
PRG=`readlink "$PRG"`
done
scriptdir=`dirname "$PRG"`
Here is the simple, correct way:
actual_path=$(readlink -f "${BASH_SOURCE[0]}")
script_dir=$(dirname "$actual_path")
Explanation:
${BASH_SOURCE[0]} - the full path to the script. The value of this will be correct even when the script is being sourced, e.g. source <(echo 'echo $0') prints bash, while replacing it with ${BASH_SOURCE[0]} will print the full path of the script. (Of course, this assumes you're OK taking a dependency on Bash.)
readlink -f - Recursively resolves any symlinks in the specified path. This is a GNU extension, and not available on (for example) BSD systems. If you're running a Mac, you can use Homebrew to install GNU coreutils and supplant this with greadlink -f.
And of course dirname gets the parent directory of the path.
I tried all of these and none worked. One was very close, but it had a tiny bug that broke it badly; they forgot to wrap the path in quotation marks.
Also a lot of people assume you're running the script from a shell, so they forget when you open a new script it defaults to your home.
Try this directory on for size:
/var/No one/Thought/About Spaces Being/In a Directory/Name/And Here's your file.text
This gets it right regardless how or where you run it:
#!/bin/bash
echo "pwd: `pwd`"
echo "\$0: $0"
echo "basename: `basename "$0"`"
echo "dirname: `dirname "$0"`"
So to make it actually useful, here's how to change to the directory of the running script:
cd "`dirname "$0"`"
This is a slight revision to the solution e-satis and 3bcdnlklvc04a pointed out in their answer:
SCRIPT_DIR=''
pushd "$(dirname "$(readlink -f "$BASH_SOURCE")")" > /dev/null && {
SCRIPT_DIR="$PWD"
popd > /dev/null
}
This should still work in all the cases they listed.
This will prevent popd after a failed pushd. Thanks to konsolebox.
Try using:
real=$(realpath "$(dirname "$0")")
I would use something like this:
# Retrieve the full pathname of the called script
scriptPath=$(which $0)
# Check whether the path is a link or not
if [ -L $scriptPath ]; then
# It is a link then retrieve the target path and get the directory name
sourceDir=$(dirname $(readlink -f $scriptPath))
else
# Otherwise just get the directory name of the script path
sourceDir=$(dirname $scriptPath)
fi
For systems having GNU coreutils readlink (for example, Linux):
$(readlink -f "$(dirname "$0")")
There's no need to use BASH_SOURCE when $0 contains the script filename.
$_ is worth mentioning as an alternative to $0. If you're running a script from Bash, the accepted answer can be shortened to:
DIR="$( dirname "$_" )"
Note that this has to be the first statement in your script.
These are short ways to get script information:
Folders and files:
Script: "/tmp/src dir/test.sh"
Calling folder: "/tmp/src dir/other"
Using these commands:
echo Script-Dir : `dirname "$(realpath $0)"`
echo Script-Dir : $( cd ${0%/*} && pwd -P )
echo Script-Dir : $(dirname "$(readlink -f "$0")")
echo
echo Script-Name : `basename "$(realpath $0)"`
echo Script-Name : `basename $0`
echo
echo Script-Dir-Relative : `dirname "$BASH_SOURCE"`
echo Script-Dir-Relative : `dirname $0`
echo
echo Calling-Dir : `pwd`
And I got this output:
Script-Dir : /tmp/src dir
Script-Dir : /tmp/src dir
Script-Dir : /tmp/src dir
Script-Name : test.sh
Script-Name : test.sh
Script-Dir-Relative : ..
Script-Dir-Relative : ..
Calling-Dir : /tmp/src dir/other
Also see: https://pastebin.com/J8KjxrPF
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.
I've compared many of the answers given, and came up with some more compact solutions. These seem to handle all of the crazy edge cases that arise from your favorite combination of:
Absolute paths or relative paths
File and directory soft links
Invocation as script, bash script, bash -c script, source script, or . script
Spaces, tabs, newlines, Unicode, etc. in directories and/or filename
Filenames beginning with a hyphen
If you're running from Linux, it seems that using the proc handle is the best solution to locate the fully resolved source of the currently running script (in an interactive session, the link points to the respective /dev/pts/X):
resolved="$(readlink /proc/$$/fd/255 && echo X)" && resolved="${resolved%$'\nX'}"
This has a small bit of ugliness to it, but the fix is compact and easy to understand. We aren't using bash primitives only, but I'm okay with that because readlink simplifies the task considerably. The echo X adds an X to the end of the variable string so that any trailing whitespace in the filename doesn't get eaten, and the parameter substitution ${VAR%X} at the end of the line gets rid of the X. Because readlink adds a newline of its own (which would normally be eaten in the command substitution if not for our previous trickery), we have to get rid of that, too. This is most easily accomplished using the $'' quoting scheme, which lets us use escape sequences such as \n to represent newlines (this is also how you can easily make deviously named directories and files).
The above should cover your needs for locating the currently running script on Linux, but if you don't have the proc filesystem at your disposal, or if you're trying to locate the fully resolved path of some other file, then maybe you'll find the below code helpful. It's only a slight modification from the above one-liner. If you're playing around with strange directory/filenames, checking the output with both ls and readlink is informative, as ls will output "simplified" paths, substituting ? for things like newlines.
absolute_path=$(readlink -e -- "${BASH_SOURCE[0]}" && echo x) && absolute_path=${absolute_path%?x}
dir=$(dirname -- "$absolute_path" && echo x) && dir=${dir%?x}
file=$(basename -- "$absolute_path" && echo x) && file=${file%?x}
ls -l -- "$dir/$file"
printf '$absolute_path: "%s"\n' "$absolute_path"
I believe I've got this one. I'm late to the party, but I think some will appreciate it being here if they 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
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:
How can I set the current working directory to the directory of the script in Bash?
Bash script absolute path with OS X
Reliable way for a Bash script to get the full path to itself
I just want to understand following line of code in shell. It is used to get the current working directory. I am aware that $(variable) name return the value inside the variable name, but what is $(command) supposed to return? Does it return the value after executing the command? In that case, we can use ` to execute the command.
CWD="$(cd "$(dirname $0)"; pwd)"
Same output can be taken from the following line of code also in different version of shell
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
I am unable to understand the meaning of $(cd.. and $(dirname.
Could anybody help me to figure out how this command get executed?
Usage of the $ like ${HOME} gives the value of HOME. Usage of the $ like $(echo foo) means run whatever is inside the parentheses in a subshell and return that as the value. In my example, you would get foo since echo will write foo to standard out
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
Could anybody help me to figure out how this command get executed?
Let's look at different parts of the command. BASH_SOURCE is a bash array variable containing source filenames. So "${BASH_SOURCE[0]}" would return you the name of the script file.
dirname is a utility provided by GNU coreutils that remove the last component from the filename. Thus if you execute your script by saying bash foo, "$( dirname "${BASH_SOURCE[0]}" )" would return .. If you said bash ../foo, it'd return ..; for bash /some/path/foo it'd return /some/path.
Finally, the entire command "$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" gets the absolute directory containing the script being invoked.
$(...) allows command substitution, i.e. allows the output of a command to replace the command itself and can be nested.
I'm writing a Bash script. I need the current working directory to always be the directory that the script is located in.
The default behavior is that the current working directory in the script is that of the shell from which I run it, but I do not want this behavior.
#!/bin/bash
cd "$(dirname "$0")"
The following also works:
cd "${0%/*}"
The syntax is thoroughly described in this StackOverflow answer.
Try the following simple one-liners:
For all UNIX/OSX/Linux
dir="$(cd -P -- "$(dirname -- "$0")" && pwd -P)"
Bash
dir="$(cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
Note: A double dash (--) is used in commands to signify the end of command options, so files containing dashes or other special characters won't break the command.
Note: In Bash, use ${BASH_SOURCE[0]} in favor of $0, otherwise the path can break when sourcing it (source/.).
*For Linux, Mac and other BSD:
cd "$(dirname "$(realpath -- "$0")")";
Note: realpath should be installed in the most popular Linux distribution by default (like Ubuntu), but in some it can be missing, so you have to install it.
Note: If you're using Bash, use ${BASH_SOURCE[0]} in favor of $0, otherwise the path can break when sourcing it (source/.).
Otherwise you could try something like that (it will use the first existing tool):
cd "$(dirname "$(readlink -f -- "$0" || realpath -- "$0")")"
For Linux specific:
cd "$(dirname "$(readlink -f -- "$0")")"
*Using GNU readlink on BSD/Mac:
cd "$(dirname "$(greadlink -f -- "$0")")"
Note: You need to have coreutils installed
(e.g. 1. Install Homebrew, 2. brew install coreutils).
In bash
In bash you can use Parameter Expansions to achieve that, like:
cd "${0%/*}"
but it doesn't work if the script is run from the same directory.
Alternatively you can define the following function in bash:
realpath () {
[[ "$1" = /* ]] && echo "$1" || echo "$PWD/${1#./}"
}
This function takes 1 argument. If argument has already absolute path, print it as it is, otherwise print $PWD variable + filename argument (without ./ prefix).
or here is the version taken from Debian .bashrc file:
function realpath()
{
f=$#
if [ -d "$f" ]; then
base=""
dir="$f"
else
base="/$(basename -- "$f")"
dir="$(dirname -- "$f")"
fi
dir="$(cd -- "$dir" && /bin/pwd)"
echo "$dir$base"
}
Related:
How to detect the current directory in which I run my shell script?
How do I get the directory where a Bash script is located from within the script itself?
Bash script absolute path with OS X
Reliable way for a Bash script to get the full path to itself
See also:
How can I get the behavior of GNU's readlink -f on a Mac?
cd "$(dirname "${BASH_SOURCE[0]}")"
It's easy. It works.
The accepted answer works well for scripts that have not been symlinked elsewhere, such as into $PATH.
#!/bin/bash
cd "$(dirname "$0")"
However if the script is run via a symlink,
ln -sv ~/project/script.sh ~/bin/;
~/bin/script.sh
This will cd into the ~/bin/ directory and not the ~/project/ directory, which will probably break your script if the purpose of the cd is to include dependencies relative to ~/project/
The symlink safe answer is below:
#!/bin/bash
cd "$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")" # cd current directory
readlink -f is required to resolve the absolute path of the potentially symlinked file.
The quotes are required to support filepaths that could potentially contain whitespace (bad practice, but its not safe to assume this won't be the case)
This script seems to work for me:
#!/bin/bash
mypath=`realpath $0`
cd `dirname $mypath`
pwd
The pwd command line echoes the location of the script as the current working directory no matter where I run it from.
There are a lot of correct answers in here, but one that tends to be more useful for me (making sure a script's relative paths remain predictable/work) is to use pushd/popd:
pushd "$(dirname ${BASH_SOURCE:0})"
trap popd EXIT
# ./xyz, etc...
This will push the source file's directory on to a navigation stack, thereby changing the working directory, but then, when the script exits (for whatever reason, including failure), the trap will run popd, restoring the current working directory before it was executed. If the script were to cd and then fail, your terminal could be left in an unpredictable state after the execution ends - the trap prevents this.
I take this and it works.
#!/bin/bash
cd "$(dirname "$0")"
CUR_DIR=$(pwd)
Get the real path to your script
if [ -L $0 ] ; then
ME=$(readlink $0)
else
ME=$0
fi
DIR=$(dirname $ME)
(This is answer to the same my question here: Get the name of the directory where a script is executed)
cd "`dirname $(readlink -f ${0})`"
Most answers either don't handle files which are symlinked via a relative path, aren't one-liners or don't handle BSD (Mac). A solution which does all three is:
HERE=$(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
echo $PWD
PWD is an environment variable.
If you just need to print present working directory then you can follow this.
$ vim test
#!/bin/bash
pwd
:wq to save the test file.
Give execute permission:
chmod u+x test
Then execute the script by ./test then you can see the present working directory.
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
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:
#!/usr/bin/env 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
$0: ./whatdirlink.sh
basename: whatdirlink.sh
dirname: .
dirname/readlink: /Users/phatblat
There is however one case where this doesn't work, when the script is sourced (instead of executed) in bash:
>>>$ cd /tmp
>>>$ . ~/whatdir.sh
pwd: /tmp
$0: bash
basename: bash
dirname: .
dirname/readlink: /tmp
pushd . > '/dev/null';
SCRIPT_PATH="${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
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]:-$0}";
while [ -h "$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 -e -- "$DIR"; )"; # Resolve its full path if need be
Short answer:
"`dirname -- "$0";`"
or (preferably):
"$( dirname -- "$0"; )"
This should do it:
DIR="$(dirname "$(realpath "$0")")"
This works with symlinks and spaces in path.
Please see the man pages for dirname and realpath.
Please add a comment on how to support MacOS. I'm sorry I can verify it.
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 -- "$0"; )";
solves the specific scenario in the question, I find having the absolute path to more more useful generally.
SCRIPT_DIR=$( cd ${0%/*} && pwd -P )
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)
$(dirname "$(readlink -f "$BASH_SOURCE")")
This is Linux specific, but you could use:
SELF=$(readlink /proc/$$/fd/255)
Here is a POSIX compliant one-liner:
SCRIPT_PATH=`dirname "$0"`; SCRIPT_PATH=`eval "cd \"$SCRIPT_PATH\" && pwd"`
# test
echo $SCRIPT_PATH
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?".
Summary:
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")"
Details:
How to obtain the full file path, full directory, and base filename of any script being run OR sourced...
...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:
Running the script:
~/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"
Sourcing the script with . 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.
References:
How to retrieve absolute path given relative
taught me about the BASH_SOURCE variable: Unix & Linux: determining path to sourced shell script
taught me that BASH_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 script
man bash --> search for BASH_SOURCE:
BASH_SOURCE
An array variable whose members are the source filenames where the corresponding shell function names in the FUNCNAME array variable are defined. The shell function ${FUNCNAME[$i]} is defined in the file ${BASH_SOURCE[$i]} and called from ${BASH_SOURCE[$i+1]}.
See also:
[my answer] Unix & Linux: determining path to sourced shell script
#!/bin/sh
PRG="$0"
# need this for relative symlinks
while [ -h "$PRG" ] ; do
PRG=`readlink "$PRG"`
done
scriptdir=`dirname "$PRG"`
Here is the simple, correct way:
actual_path=$(readlink -f "${BASH_SOURCE[0]}")
script_dir=$(dirname "$actual_path")
Explanation:
${BASH_SOURCE[0]} - the full path to the script. The value of this will be correct even when the script is being sourced, e.g. source <(echo 'echo $0') prints bash, while replacing it with ${BASH_SOURCE[0]} will print the full path of the script. (Of course, this assumes you're OK taking a dependency on Bash.)
readlink -f - Recursively resolves any symlinks in the specified path. This is a GNU extension, and not available on (for example) BSD systems. If you're running a Mac, you can use Homebrew to install GNU coreutils and supplant this with greadlink -f.
And of course dirname gets the parent directory of the path.
I tried all of these and none worked. One was very close, but it had a tiny bug that broke it badly; they forgot to wrap the path in quotation marks.
Also a lot of people assume you're running the script from a shell, so they forget when you open a new script it defaults to your home.
Try this directory on for size:
/var/No one/Thought/About Spaces Being/In a Directory/Name/And Here's your file.text
This gets it right regardless how or where you run it:
#!/bin/bash
echo "pwd: `pwd`"
echo "\$0: $0"
echo "basename: `basename "$0"`"
echo "dirname: `dirname "$0"`"
So to make it actually useful, here's how to change to the directory of the running script:
cd "`dirname "$0"`"
Try using:
real=$(realpath "$(dirname "$0")")
This is a slight revision to the solution e-satis and 3bcdnlklvc04a pointed out in their answer:
SCRIPT_DIR=''
pushd "$(dirname "$(readlink -f "$BASH_SOURCE")")" > /dev/null && {
SCRIPT_DIR="$PWD"
popd > /dev/null
}
This should still work in all the cases they listed.
This will prevent popd after a failed pushd. Thanks to konsolebox.
I would use something like this:
# Retrieve the full pathname of the called script
scriptPath=$(which $0)
# Check whether the path is a link or not
if [ -L $scriptPath ]; then
# It is a link then retrieve the target path and get the directory name
sourceDir=$(dirname $(readlink -f $scriptPath))
else
# Otherwise just get the directory name of the script path
sourceDir=$(dirname $scriptPath)
fi
For systems having GNU coreutils readlink (for example, Linux):
$(readlink -f "$(dirname "$0")")
There's no need to use BASH_SOURCE when $0 contains the script filename.
$_ is worth mentioning as an alternative to $0. If you're running a script from Bash, the accepted answer can be shortened to:
DIR="$( dirname "$_" )"
Note that this has to be the first statement in your script.
These are short ways to get script information:
Folders and files:
Script: "/tmp/src dir/test.sh"
Calling folder: "/tmp/src dir/other"
Using these commands:
echo Script-Dir : `dirname "$(realpath $0)"`
echo Script-Dir : $( cd ${0%/*} && pwd -P )
echo Script-Dir : $(dirname "$(readlink -f "$0")")
echo
echo Script-Name : `basename "$(realpath $0)"`
echo Script-Name : `basename $0`
echo
echo Script-Dir-Relative : `dirname "$BASH_SOURCE"`
echo Script-Dir-Relative : `dirname $0`
echo
echo Calling-Dir : `pwd`
And I got this output:
Script-Dir : /tmp/src dir
Script-Dir : /tmp/src dir
Script-Dir : /tmp/src dir
Script-Name : test.sh
Script-Name : test.sh
Script-Dir-Relative : ..
Script-Dir-Relative : ..
Calling-Dir : /tmp/src dir/other
Also see: https://pastebin.com/J8KjxrPF
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.
I've compared many of the answers given, and came up with some more compact solutions. These seem to handle all of the crazy edge cases that arise from your favorite combination of:
Absolute paths or relative paths
File and directory soft links
Invocation as script, bash script, bash -c script, source script, or . script
Spaces, tabs, newlines, Unicode, etc. in directories and/or filename
Filenames beginning with a hyphen
If you're running from Linux, it seems that using the proc handle is the best solution to locate the fully resolved source of the currently running script (in an interactive session, the link points to the respective /dev/pts/X):
resolved="$(readlink /proc/$$/fd/255 && echo X)" && resolved="${resolved%$'\nX'}"
This has a small bit of ugliness to it, but the fix is compact and easy to understand. We aren't using bash primitives only, but I'm okay with that because readlink simplifies the task considerably. The echo X adds an X to the end of the variable string so that any trailing whitespace in the filename doesn't get eaten, and the parameter substitution ${VAR%X} at the end of the line gets rid of the X. Because readlink adds a newline of its own (which would normally be eaten in the command substitution if not for our previous trickery), we have to get rid of that, too. This is most easily accomplished using the $'' quoting scheme, which lets us use escape sequences such as \n to represent newlines (this is also how you can easily make deviously named directories and files).
The above should cover your needs for locating the currently running script on Linux, but if you don't have the proc filesystem at your disposal, or if you're trying to locate the fully resolved path of some other file, then maybe you'll find the below code helpful. It's only a slight modification from the above one-liner. If you're playing around with strange directory/filenames, checking the output with both ls and readlink is informative, as ls will output "simplified" paths, substituting ? for things like newlines.
absolute_path=$(readlink -e -- "${BASH_SOURCE[0]}" && echo x) && absolute_path=${absolute_path%?x}
dir=$(dirname -- "$absolute_path" && echo x) && dir=${dir%?x}
file=$(basename -- "$absolute_path" && echo x) && file=${file%?x}
ls -l -- "$dir/$file"
printf '$absolute_path: "%s"\n' "$absolute_path"
I believe I've got this one. I'm late to the party, but I think some will appreciate it being here if they 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
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:
How can I set the current working directory to the directory of the script in Bash?
Bash script absolute path with OS X
Reliable way for a Bash script to get the full path to itself