Reliable way for a Bash script to get the full path to itself
I just had to revisit this issue today and found Get the source directory of a Bash script from within the script itself:
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
There's more variants at the linked answer, e.g. for the case where the script itself is a symlink.
The simplest way that I have found to get a full canonical path in Bash is to use cd
and pwd
:
ABSOLUTE_PATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/$(basename "${BASH_SOURCE[0]}")"
Using ${BASH_SOURCE[0]}
instead of $0
produces the same behavior regardless of whether the script is invoked as <name>
or source <name>
.
Here's what I've come up with (edit: plus some tweaks provided by sfstewman, levigroker, Kyle Strand, and Rob Kennedy), that seems to mostly fit my "better" criteria:
SCRIPTPATH="$( cd -- "$(dirname "$0")" >/dev/null 2>&1 ; pwd -P )"
That SCRIPTPATH
line seems particularly roundabout, but we need it rather than SCRIPTPATH=`pwd`
in order to properly handle spaces and symlinks.
The inclusion of output redirection (>/dev/null 2>&1
) handles the rare(?) case where cd
might produce output that would interfere with the surrounding $( ... )
capture. (Such as cd
being overridden to also ls
a directory after switching to it.)
Note also that esoteric situations, such as executing a script that isn't coming from a file in an accessible file system at all (which is perfectly possible), is not catered to there (or in any of the other answers I've seen).
The --
after cd
and before "$0"
are in case the directory starts with a -
.
I'm surprised that the realpath
command hasn't been mentioned here. My understanding is that it is widely portable / ported.
Your initial solution becomes:
SCRIPT=$(realpath "$0")
SCRIPTPATH=$(dirname "$SCRIPT")
And to leave symbolic links unresolved per your preference:
SCRIPT=$(realpath -s "$0")
SCRIPTPATH=$(dirname "$SCRIPT")