Retaining file modification times

[Lee Phillips]

I want to do something to a file without changing its modification
time.  I suppose I can write a script to get the time from ls, do the
modification, then restore the time (after converting it to numerical
format) with /usr/5bin/touch, but I'm hoping that there is an easier
way. (Csh solutions preferred.) 
--
                                           Lee Phillips
                                           phillips at fozzie.nrl.navy.mil
                                           phillips at lcp.nrl.navy.mil