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2011-03-12 - Confoo 2011 presentation
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2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.




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 265 weeks and 1 day ago

bc does floating point, large powers and trig functions too



bc -l




Comment by Escher 265 weeks and 1 day ago

the comment above came out wrong

bc <<< 512*7


bc -l <<< 512/7


bc <<< 512^7


Comment by Escher 265 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 265 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 265 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 265 weeks ago
bc <<< 512*7

is 12 keystrokes

expr 512 \* 7

is 13 keystrokes

Comment by Escher 265 weeks ago

and in fact, it could just be


which is 10 keystrokes.

Comment by Escher 265 weeks ago

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

Comment by chuckr 265 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 265 weeks ago

Your point of view

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