hi i have joined this forum just now

[ASKhubalkar]

hi, i want to know how can we use command 'head' and 'tail' work in a single statement to retrieve top n bottom line of a file.individually i know but how to do in a single command line.plz lets me now

[Irithori]

hi and welcome.

The following is far from elegant and in fact downright ugly.

head /var/log/messages > /tmp/tmp_file && tail /var/log/messages >> /tmp/tmp_file && cat /tmp/tmp_file && rm -f /tmp/tmp_file

For more than occasional use, you might want to think about a shell wrapper, parameters, errorconditions and secure tmp file creation..

[Irithori]

ah sorry, no need for a tmp file.

this will do:

head /var/log/messages && tail /var/log/messages

[ASKhubalkar]

actually i want to get process which uses maximum memory usage n minimum memory usage.
for maximum i used
ps -auxf | sort -nr -k 4 | head -1
it works n
tail -1 to get minimum
but instead of typing two lines can i do this in a single line.

[Irithori]

You can try this:

ps auxf | sort -nr -k 4|pee "head -1" "tail -1"

The "pee" command is part of the moreutils package.


P.S.
The coffee lounge seems not the best place for questions like these.
It would have been better placed in Linux Applications.
Well, next time