Linux delete egrepped lines

Question

I pass file to my egrep expression (tcpdump log), then I want to delete all matched lines

Code example:

cat file | tr -d '\000' |egrep -i 'user: | usr: ' --color=auto --line-buffered -B20

How can I delete all matched lines now?

score 2 · Accepted Answer · answered Apr 03 '17 at 10:24

2

Use -v flag

 -v, --invert-match
         Selected lines are those not matching any of the specified patterns.

cat file | tr -d '\000' |egrep -iv 'user: | usr: ' --color=auto --line-buffered -B20 > newfile

answered Apr 03 '17 at 10:24

Dmitry Shilyaev

It deleted something, but grepping with the same regex on new file still does show me some entries (I believe it should now) // Deleting line formatting did the job for me - thanks! – Jakub Pastuszuk Apr 03 '17 at 10:29
Case of `UUOC`. A single `sed` can do the job of both `tr + grep` and moreover bonus of inline file editing. – anubhava Apr 03 '17 at 10:33
That is just the bonus part – anubhava Apr 03 '17 at 10:49
along with the accidental file corruption ;) – Dmitry Shilyaev Apr 03 '17 at 10:53
You probably don't know about inline editing and saving original as backup using `-i .bak` option – anubhava Apr 03 '17 at 11:01

anubhava · Answer 2 · 2017-04-03T10:29:40.393

0

You can do all that using sed:

sed -iE '/use?r: /d; s/\x0//g' file

edited Apr 03 '17 at 10:29

answered Apr 03 '17 at 10:23

anubhava

2 Answers2