Help Running Loop Script

Shell Programming and Scripting
1

Hi

I have a file called lastlogin_1 that contains a list of usernames. I would like to put together a quick loop script that will use a variable (the contents of lastlogin_1 file) and grep all directories and sub directories in the current directory (/in/the/current/directory) for each username in the lastlogin_1 file and remove all entries of the usernames that exist in files under these directories.

The files contain information as follows: (user access to various menus)

:allow:davidw,simonk,katrinad,elizabeo,rachelm,jodiew,carolep,timj,colleenh,audreys,angelal:

The lastlogin_1 file contains entries as follows:
jamesm> more lastlogin_1
aaron
adamb
alan
alanr
alanr
alecia
aleda
alexs
alfred

Should the username be removed it will leave a double comma ,, in the file which might cause problems with other users access so I would like to remove only the comma following the user being removed.

Can someone point me in the right direction of how to do this with the use of a script. I have tried a few things but failing at the first hurdle when trying to set the variable ie

USERS=${<Lastlogin_1} or USERS= awk '{print $1}' lastlogin_1

Thanks in advance

2 
$ cat lastlogin_1
:allow:davidw,simonk,katrinad,elizabeo,rachelm,jodiew,carolep,timj,colleenh,audreys,angelal:

#!/bin/bash
USERS=$(awk -F: '{print $3}' lastlogin_1 | tr ',' '\n')
for U in $USERS
do
    echo "$U" # Just for testing purpose
    # and further processing
done
3

A separate variable is not needed

awk -F: '{print $3}' lastlogin_1 | tr ',' '\n' | while read user
do
  echo $user
done
4

Thanks for the responses. Using the following (changed to $1)

USERS=$(awk -F: '{print $1}' lastlogin_1 | tr ',' '\n')
for U in $USERS
do
    echo "$U" # Just for testing purpose
    # and further processing
done

outputs what is already in the lastlogin_1 file, as does

USERS=$(awk -F: '{print $1}' lastlogin_1)
for U in $USERS
do
    echo "$U" # Just for testing purpose
    # and further processing
done

I have many files in various directories and sub-directories that contain all the users in the variable $USERS. I would like to remove each user from every file they exist in under the main
directory= /apps/fourgen/accounting/menu.

The files that contain the users I want to remove have the following format

:allow:davidw,simonk,katrinad,elizabeo,rachelm,jodiew,carolep,timj,colleenh,audreys,angelal:

Now that I have the variable $USERS how do I search every file from the main directory including all sub-directories and remove all existing entries for each username within the variable.

More help appreciated.. Thanks