grep issue

Volcano · 07-07-2015, 10:35 AM

I have a command

cat catalina.log | grep "CTC="

I want to list matches from last of the log files (i.e latest records first )

what changes do I require in my command ?

bigrigdriver · 07-07-2015, 11:14 AM

Use the tail command instead of cat. Tail reads the file from the end of the file in reverse order. You can also specify the number of lines for tail to read.

Code:

tail -n 20 catalina.log | grep "CTC="

See the tail man page for more information.

Volcano · 07-07-2015, 11:51 AM

Quote:

Originally Posted by bigrigdriver

Use the tail command instead of cat. Tail reads the file from the end of the file in reverse order. You can also specify the number of lines for tail to read.

Code:

tail -n 20 catalina.log | grep "CTC="

See the tail man page for more information.

This looks good.

If I want to see 5 lines above and below for each of these matches ...what will be command ?

Is it this ?

tail -n 20 catalina.log | grep "CTC=" -A 5 -B 5

HMW · 07-07-2015, 01:54 PM

Quote:

Originally Posted by Volcano

If I want to see 5 lines above and below for each of these matches ...what will be command ?

Is it this ?

tail -n 20 catalina.log | grep "CTC=" -A 5 -B 5

Well, almost. This should work:

Code:

tail -n 20 catalina.log | grep -C 5 "CTC="

The '-C' flag covers both before and after.