Is it possible, executing a file symlinked in /usr/local/bin
folder, to get the absolute path of original script? Well, .. I know where original file is, and I know it because I am linkging it. But, ... I want this script working, even if I move original source code (and symlink).
#!/bin/bash echo "my path is ..."
The accepted answer to Getting the source directory of a Bash script from within addresses getting the path of the script via dirname $0 , which is fine, but that may return a relative path (like . ), which is a problem if you want to change directories in the script and have the path still point to the script's ...
In order to follow symbolic links, you must specify ls -L or provide a trailing slash. For example, ls -L /etc and ls /etc/ both display the files in the directory that the /etc symbolic link points to. Other shell commands that have differences due to symbolic links are du, find, pax, rm and tar.
readlink
is not a standard command, but it's common on Linux and BSD, including OS X, and it's the most straightforward answer to your question. BSD and GNU readlink implementations are different, so read the documentation for the one you have.
If readlink
is not available, or you need to write a cross-platform script that isn't bound to a specific implementation:
If the symlink is also a directory, then
cd -P "$symlinkdir"
will get you into the dereferenced directory, so
echo "I am in $(cd -P "$symlinkdir" && pwd)"
will echo the fully dereferenced directory. That said, cd -P
dereferences the entire path, so if you have more than one symlink in the same path you can have unexpected results.
If the symlink is to a file, not a directory, you may not need to dereference the link. Most commands follow symlinks harmlessly. If you simply want to check if a file is a link, use test -L
.
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