Show Next Few Lines with grep

Now and then I have to find some information in text files – logs, config files, etc. with a unique enough approach: I have a hostname or parameter name to search by, but the actual information I'm interested in is not found in the same line. Simple grep will just not do – so I'm using one of the really useful command line options for the grep command.

Default grep Behaviour

By default, grep shows you just the lines of text files that match the parameter you specify.

I'm looking for the IP address of the home office server called "server" in .ssh/config file.

Here's what default grep shows me:

greys@maverick:~ $ grep server .ssh/config
Host server

So it's useful in a sense that this confirms that I indeed have a server profile defined in my .ssh/config file, but it doesn't show any more lines of the config so I can't really see the IP address of my "server".

Show Next Few Lines with grep

This is where the -A option (A – After) for grep becomes really useful: specify number of lines to show in addition to the line that matches search pattern and enjoy the result!

I'm asking grep to show me 2 more lines after the "server" line:

greys@maverick:~ $ grep -A2 server .ssh/config
Host server
     HostName 192.168.1.55
     ForwardAgent yes

Super simple but very powerful way of using grep. I hope you like it!

See Also

• grep command
• Basic Unix commands
• Advanced Unix commands
• tail and awk for inspecting logs
• tail command