This script lists all commands that appear more than once in your $PATH. For of each command its locations and the number of occurrences are displayed.

multibin.sh

#!/bin/bash
# 
# This script lists all commands that appear more than once in your $PATH.
# For of each command its locations and the number of occurrences are displayed.
#
# Nils Breunese <nils@breun.nl>, 2012.

for command in `compgen -c`
do
    count=`which -a $command | wc -l | tr -d ' '`
    if [ "$count" -gt "1" ]
    then
        echo "$command: `which -a $command | tr '\n' ' '`($count)"
    fi
done