~/script/perl/temp@myserver >ls -li done.txt*
     35466 -rw-rw-r--   2 xmen    xmen          54 Aug  7 17:51 done.txt
     35467 -rw-rw-r--   1 xmen    xmen          0 Aug  7 17:51 done.txt2
     35466 -rw-rw-r--   2 xmen    xmen          54 Aug  7 17:51 done.txt_ln
~/script/perl/temp@myserver >cat done.txt
yahoo never yahoo
never never never
yahoo yahoo yahoo
~/script/perl/temp@myserver >cat done.txt_ln
yahoo never yahoo
never never never
yahoo yahoo yahoo
~/script/perl/temp@myserver >cat perl.file
#!/usr/bin/perl -w

use strict;
open(FH,'done.txt');

while (<FH>) {
  s/yahoo/never/g;
  print;
}
close(FH);
~/script/perl/temp@myserver >./perl.file done.txt > done.txt_ln
~/script/perl/temp@myserver >ls -li done.txt*
     35466 -rw-rw-r--   2 xmen    xmen         0 Aug  7 17:56 done.txt
     35467 -rw-rw-r--   1 xmen    xmen            0 Aug  7 17:51 done.txt2
     35466 -rw-rw-r--   2 xmen    xmen           0 Aug  7 17:56 done.txt_ln