Sometime a script needs to now the directory that it is executing from, the best solution for this is:

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

Although the simpler version below should work for most cases the version above is preferred for shell portability.

DIR=`dirname $0`

The usage of this could be for creating shell scripts that a user can double click to execute or drag on to the terminal to execute, as the working directory could change. Uses the scripts folder means that if a user copies the script to a new project it will work in the new project rather than having absolute paths to the old project.

#!/bin/bash

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
CSS_COLLATION=$DIR/screen.css

#Clean File
echo '' > $CSS_COLLATION

#Append CSS
cat $DIR/reset.css >> $CSS_COLLATION
cat $DIR/960.css >> $CSS_COLLATION

From StackOverflow