1. To display the first 10 lines of /var/adm/messages.
head -10 /var/adm/messages
2. To display the last 10 lines of /var/adm/messages.
tail -10 /var/adm/messages
3. To display lines in between 10-50 of /var/adm/messages.
sed -n '10,50p' /var/adm/messages
