CODEWITHSUNDEEP
linuxunix
jingo
jingo

Reputation: 1074

Exploring file with tail command

I'm using tail -f for watching log files in "real time". What to do so be able to view only lines containig 127.0.0.1 for example ?

Upvotes: 1

Views: 243

Answers (4)

Rahul
Rahul

Reputation: 77876

In case you want to grep all the lines containing any IP address and not only 127.0.0.1 then

tail -f filename|grep '^[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}$'

Upvotes: 1

Bruce ONeel
Bruce ONeel

Reputation: 2149

Watch is also a cool command for this

watch grep '127.0.0.1' foo

and it will update every 2 seconds.

Upvotes: 2

sarnold
sarnold

Reputation: 104080

tail -f /path/to/log/file | grep --line-buffered 127.0.0.1

The --line-buffered is not strictly needed for grep(1) in this case, but it would be if you wanted to send output to less(1) or some further processing steps, and still wanted to see individual lines as they were logged. (See setvbuf(3) for full details on the buffering.)

Upvotes: 4

thiton
thiton

Reputation: 36049

grep is your friend:

 tail -f foo | grep '127\.0\.0\.1'

Upvotes: 7

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