A command line calculator in Perl

perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;'
Once I wrote a command line calculator program in C, then I found this... and added to it a bit. For ease of use I normally use this in a tiny Perl program (which I call pc for 'Perl Calculator') #!/usr/bin/perl -w die "Usage: $0 MATHS\n" unless(@ARGV);for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g}; print eval(join('',@ARGV)),$/; It handles square roots, power, modulus: pc 1+2 (1 plus 2) 3 pc 3x4 (3 times 4) 12 pc 5^6 (5 to the power of 6) 15625 pc v 49 ( square root of 49 ) 7 pc 12/3 (12 divided by 3) 4 pc 19%4 (19 modulus 4) 3 (you can string maths together too) pc 10 x 10 x 10 1000 pc 10 + 10 + 10 / 2 25 pc 7 x v49 49
Sample Output
$ perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;' 1+2
3
$ perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;' 3x4
12
$ perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;' 5^6
9
$ perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;' v9
3
$ perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;' 9/4
2.25
$ perl -e 'for(@ARGV){s/x/*/g;s/v/sqrt /g;s/\^/**/g};print eval(join("",@ARGV)),$/;' 19%4
3

2
By: JohnGH
2009-12-21 21:03:27

What Others Think

Neat! zsh does some of this stuff also, which I was happy to learn recently, using double-parentheses $((1+1)) or single square brackets $[1+1]: zsh-> print $((5**6)) zsh-> print $((5**0.5)) zsh-> print $[19 % 4] also does bitwise shift >>, ++/-- in/decrementing
bwoodacre · 516 weeks and 2 days ago
bashisms: bc <<< 1+1 echo $((1+1))
rbossy · 516 weeks and 1 day ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

You must be signed in to comment.

What's this?

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

Share Your Commands



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: