What if I want to keep the last 2 or 3 or n number of modified file in the directory and move/copy the rest of the files.

well, then i would do something completely different...

$ ls -t whacl-*
whacl-20030608223002.gz
whacl-20030607223001.gz
whacl-20030606223002.gz
whacl-20030605223003.gz

$ ls -t whacl-* | sed "1,1d"
whacl-20030607223001.gz
whacl-20030606223002.gz
whacl-20030605223003.gz

$ ls -t whacl-* | sed "1,2d"
whacl-20030606223002.gz
whacl-20030605223003.gz

$ ls -t whacl-* | sed "1,3d"
whacl-20030605223003.gz

$ ls -t whacl-* | sed "1,2d" | while read file; do echo 'cp' $file /de
+v/null; done
cp whacl-20030606223002.gz /dev/null
cp whacl-20030605223003.gz /dev/null

$ ls -t whacl-* | sed "1,2d" | while read file; do echo 'cp' $file /de
+v/null; echo 'rm' $file; done | sh

$ ls -t whacl-*
whacl-20030608223002.gz
whacl-20030607223001.gz
[download]

hi zengargoyle, Very sorry for the interruption again. Here is the query from my colleague again. What if I want to keep the last 5 hour modified file in the directory and move/copy the rest of the files. That is, those last modified files which dated within the last 5 hour will be keep. Hope to hear you soon. Thanks. rgds, hyliau

Here is the query from my colleague again. What if I want to keep the last 5 hour modified file in the directory and move/copy the rest of the files.

you should tell your colleague to stop changing the requirements. things are now complicated enough that a perl solution would be better than a shell solution. see the other responses in the thread for pointers in that direction.