I'm transferring a shell application from SCO 5.0.5 to RedHat 7.0. Of all the things that I thought I would have no problems with, I never thought that the speed of the sed command on SCO would run 4 times faster than the one on RedHat! The original sed on SCO had been running slowly - so I had compiled the GNU version of sed on SCO - and had reduced the execution time from 3 hours to 40 minutes. Now I have transferred the exact same script that calls sed extensively from SCO to the standard, stock RedHat 7.0 distribution - I find that the RedHat sed is running 4 times slower than than the SCO GNU version of sed - just like the original SCO sed. Isn't the version that comes with RedHat the GNU version already? The RPM reveals that RedHat sed is "sed 3.02-8". I'm such a newbie that I don't even know how to update to the latest version of sed - and don't know if it would help? What am I missing? TIA. David.