UNIX for Dummies Questions & Answers

Actually, my example above isn't the case - the leading / will protect it from matching the a in local. But it could break another way easily enough.

It's a matter of restricting the change to the right bit of the path...
Depending on what the OP actually wants, you could isolate each path element:

Code:

#!/bin/sh
elements="$PATH"
while [ -n "$elements" ]
do
    element=`echo $elements | cut -d ':' -f 1`
    elements=`echo $elements | cut -d ':' -f 2-`
    candidate=`basename $element`
    if grep -E "^${candidate}:" /etc/passwd > /dev/null
    then
      #it's a username
     element=`dirname $element`
    fi
    if [ -z "$result" ]
    then
      $result=$element
    else
      result="${result}:${element}"
    fi
done
echo $result

PATH=`scriptname.sh` ; export PATH
(untested so expect the odd bug)

But that's probably not required as a more careful pattern match is likely to be sufficient (again, this would depend on the O/Ps intent)
Something like:

Code:

PATH=`echo $PATH | sed 's/\/USERNAME[\:$]//g'`

My sed's not the best but you get the picture.