Shell Programming and Scripting

Aloha! I have just over 1k of users that have permissions that they shouldn't under our system. I need to parse a provided list of usernames, check their permissions file, and strip the permissions that they are not allowed to have. If upon the permissions strip they are left with no permissions, I need have a basic permissions line added to their permission file. I am creating this script so our helpdesk guys can use it later because I can see something similar happening again.

Everything on the following script works correctly unless the user has no permissions left. The sed statement will display the correct insertion but will not overwrite the file. I have also tried piping it to cat and then redirect to the file but that just appends....Please Help!!

Oh! BTW this is in Korn shell under AIX 5.3
Also FYI permission lines are always first in the file and they are the only lines that start with numerals.

Code:

echo "Where is the user Listing?"

read usrList

usrName=""

fChar=""

while [ 1 ]

do

  read usrName || break

      sudo sed -e '/APCLERK/d' /home/$usrName/.facet | cat >> /home/testdir/$usrName
  
      fChar=`head -c 1 /home/testdir/$usrName`

          if [[ $fChar != [0-9] ]]

          then

            sudo sed -f /home/testdir/sedInqIns.sed /home/testdir/$usrName > /home/testdir/$usrName

          fi                         

      


done < $usrList

Here is the sed insert file::

Code:

1,1{
 i\
1       /PRISM/SD-START "INQUIRY~      ; ; ; ;Y;   ;    ;0000;      ;    ;Y;      ; ;      ;     ~~"
 }

On execution of this script the users that have no permissions are left with a completely blank file (there should be other settings in the file besides permissions). The users that have other permissions are fine.

Any help will be greatly appreciated.
Mahalo!!