How do I manipulate $PATH elements in shell scripts?

Question

Is there a idiomatic way of removing elements from PATH-like shell variables?

That is I want to take

PATH=/home/joe/bin:/usr/local/bin:/usr/bin:/bin:         


        

Answer 1

For deleting an element you can use sed:

#!/bin/bash
NEW_PATH=$(echo -n $PATH | tr ":" "\n" | sed "/foo/d" | tr "\n" ":")
export PATH=$NEW_PATH

will delete the paths that contain "foo" from the path.

You could also use sed to insert a new line before or after a given line.

Edit: you can remove duplicates by piping through sort and uniq:

echo -n $PATH | tr ":" "\n" | sort | uniq -c | sed -n "/ 1 / s/.*1 \(.*\)/\1/p" | sed "/foo/d" | tr "\n" ":"