#! /bin/bash 
#
#  Filename:  whois
#
#  From Mark Sobell's Red Hat Linux book.  Adapted by Br. David Carlson.
#
#  Date:  March 26, 2007
#
#  This script, when given usernames, fullnames, or partial names as parameters,
#  prints the usernames and fullnames for all accounts that match.

if [ $# -eq 0 ]
then
   echo "Syntax:  whois <user(s)>" 1>&2
   exit 1
fi

# Produce a temp file of all usernames and fullnames:
temp="/tmp/whois.$$"
cat /etc/passwd | cut -d':' -f1,5 > "$temp"

# Look for matches:
for user in "$@"
do
   grep -i "$user" "$temp"
done

rm -f "$temp"
exit 0