grep exclude multiple strings

Question

I am trying to see a log file using tail -f and want to exclude all lines containing the following strings:

Nopaging the limit is and keyword to remove is

I am able to exclude one string like this:

tail -f admin.log|grep -v "Nopaging the limit is"

But how do I exclude lines containing either of string1 or string2?

Answer 1

Filtering out multiple lines with grep:

Put these lines in filename.txt to test:

abc
def
ghi
jkl

grep command using -E flag with a pipe between tokens in a string:

grep -Ev 'def|jkl' filename.txt

prints:

abc
ghi

egrep using -v flag with pipe between tokens surrounded by parens:

egrep -v '(def|jkl)' filename.txt

prints:

abc
ghi

Or if stacking -e flags through grep parameters is okay (credit -> @Frizlab):

grep -Fv -e def -e jkl filename.txt

prints:

abc
ghi

Answer 2

If you want to use regex:

grep -Ev -e "^1" -e '^lt' -e 'John'

Answer 3

grep -Fv -e 'Nopaging the limit is' -e 'keyword to remove is'

-F matches by literal strings (instead of regex)

-v inverts the match

-e allows for multiple search patterns (all literal and inverted)

Answer 4

The greps can be chained. For example:

tail -f admin.log | grep -v "Nopaging the limit is" | grep -v "keyword to remove is"

Answer 5

You can use regular grep like this:

tail -f admin.log | grep -v "Nopaging the limit is\|keyword to remove is"

Answer 6

tail -f admin.log|grep -v -E '(Nopaging the limit is|keyword to remove is)'

Answer 7

Another option is to create a exclude list, this is particulary usefull when you have a long list of things to exclude.

vi /root/scripts/exclude_list.txt

Now add what you would like to exclude

Nopaging the limit is
keyword to remove is

Now use grep to remove lines from your file log file and view information not excluded.

grep -v -f /root/scripts/exclude_list.txt /var/log/admin.log

Answer 8

egrep -v "Nopaging the limit is|keyword to remove is"