There can be many reasons why you'd want to get the exact location of your currently running script. For example to calculate the relative path in a reliable way.

Luckily there is a command called realpath that will calculate and print the absolute path of a given path.

Let's see how it works:

examples/shell/absolute.sh

#!/bin/bash

echo $0

full_path=$(realpath $0)
echo $full_path

dir_path=$(dirname $full_path)
echo $dir_path

$0 is the name of the current script as it was executed. So if we run the script as ./examples/shell/absolute.sh then that will be the content of $0.

realpath prints the abosulte path.

dirname prints the directory name, leaving the last part of the path which is in this case the name of the file.

Let's see a couple of examples: 

$ ./examples/shell/absolute.sh

./examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell


$ cd examples/shell/
$ ./absolute.sh                                                      # run right where it is

./absolute.sh
/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell


$ cd ../../sites/en                                                  # go to a cousin of the scripts directory
$ ../../examples/shell/absolute.sh                                   # run relatively from there

../examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell


$ ln -s ../../examples/shell/                                        # create a symbolic link to the directory
$ ./shell/absolute.sh                                                # run using the symlink

./shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell


$ ln -s ../../examples/shell/absolute.sh                             # create a symlink to the script
$ ./absolute.sh                                                      # run using the symlink

./absolute.sh
/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell


$ /home/gabor/work/code-maven.com/examples/shell/absolute.sh         # run with full path

/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell/absolute.sh
/home/gabor/work/code-maven.com/examples/shell