[SOLVED] Grep regex to select only 10 character

Issue

I have a log file that I'm grep(ing) to select certain character.

The pattern of the log file looks like this

Some Random string.... Message Sent [10 character --

What I'm interested in only the 10 character string present between [ and --

I have successfully managed to compose the regex that look like this

"Message Sent \[.\{10\} --" 

I have cross checked the above regex over here.

But unfortunately the regex does not yield any output

grep -o "Message Sent \[.\{10\}) --" log/development.log

But I'm mostly interested in the 10 character but the above regex yield 'Message Sent [' + 10 character + --

Any Clue ?

Solution

Use \K (pattern from Perl-regex) to discard the previously matched chars.

grep -oP 'Message Sent \[\K.{10}(?= -+)' log/development.log

or

grep -oP 'Message\s+Sent\s+\[\K.{10}(?=\s+-+)' log/development.log

DEMO

Answered By - Avinash Raj