Grep - get first and last line

Last time I had to search my logs for certain message. I needed to connect this with user login/logout time.

I needed estimated time of "start" and "end " occurences in logs ( logs which contains huge messages with different time and same message).

I used sed and grep to this:

root@testing:~# for i in `ls /var/log/syslog/syslog*`;do zgrep 'port 1099' $i | sed -n '1p;$p'; done; Jun 25 08:18:01 testing sshd[33286]: error: connect_to x.y.z.c port 1099: failed. Jun 25 11:30:52 testing sshd[45831]: error: connect_to x.y.z.d port 1099: failed. Jun 24 07:55:04 testing sshd[64527]: error: connect_to x.y.z.d port 1099: failed. Jun 24 11:53:13 testing sshd[64527]: error: connect_to x.y.z.c port 1099: failed. Jun 23 08:59:52 testing sshd[34130]: error: connect_to x.y.z.c port 1099: failed. Jun 23 15:28:38 testing sshd[34130]: error: connect_to x.y.z.d port 1099: failed. Jun 20 08:24:51 testing sshd[64526]: error: connect_to x.y.z.c port 1099: failed. Jun 20 10:55:46 testing sshd[7805]: error: connect_to x.y.z.c port 1099: failed.