What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Universal configuration monitoring and system of record for IT.

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:



May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

Top Tags



Quick command line math

Terminal - Quick command line math
expr 512 \* 7
2009-09-23 19:11:38
User: chuckr
Functions: expr
Quick command line math

expr will give you a quick way to do basic math from the CLI. Make sure you escape things like * and leave a space between operators and digits.


There is 1 alternative - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

Doesn't do decimals. Try this Perl command.

perl -le 'print 51.2 * 2'

Comment by billbose 345 weeks and 1 day ago

bc does floating point, large powers and trig functions too



bc -l




Comment by Escher 345 weeks and 1 day ago

the comment above came out wrong

bc <<< 512*7


bc -l <<< 512/7


bc <<< 512^7


Comment by Escher 345 weeks and 1 day ago

if you don't care about decimals then try

echo $((512*7))

you don't need to care about spaces nor escaping anything

Comment by edo 345 weeks and 1 day ago

All good solutions too. But the original wins for fewest number of keystrokes :-)

Also, the bc example above seems wrong.

echo "512*7" | bc

will work.

Comment by chuckr 345 weeks and 1 day ago

the bc examples use bash 'here string' operator, it won't work in other shells, but in bash it's the fewest keystrokes, and more versatile.

Comment by Escher 345 weeks ago
bc <<< 512*7

is 12 keystrokes

expr 512 \* 7

is 13 keystrokes

Comment by Escher 345 weeks ago

and in fact, it could just be


which is 10 keystrokes.

Comment by Escher 345 weeks ago

OK. I wasn't using bash when trying the '

Comment by chuckr 345 weeks ago

OK. I wasn't using bash when trying the 'here string' solution so I didn't count its keystrokes. Good solution, if using bash.

Comment by chuckr 345 weeks ago

Your point of view

You must be signed in to comment.