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Re: Recomended tutoial(s) on doing arithmetic in Bash scripts




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On Sun, Mar 05, 2017 at 11:48:47AM -0800, David Christensen wrote:
> On 03/05/2017 07:42 AM, Richard Owlett wrote:
> >I'm interested in "expr" and "bc".
> >The man pages lack reasonable examples.
> >The tutorial/HOWTO pages confuse the issue with fancy page layouts
> >and/or code samples showing how impressive the author can make the
> >script's output.
> >
> >Suggestions please.
> 
> https://www.perl.org/

Perl's a nice language. But *if* you are doing things in shell and
just need to reach out to a small util to do a small thing (The
Shell Way, so to speak) you are better off with small utilities:

  tomas@rasputin:~$ time dc -e "2 2 + p"
  4
  
  real    0m0.004s
  user    0m0.000s
  sys     0m0.000s
  
  tomas@rasputin:~$ time perl -e "print 2 + 2"
  4
  real    0m0.011s
  user    0m0.012s
  sys     0m0.000s

Of course, if your program becomes complicated, Perl (or Guile, or
Python, or Lua or what not) will be a better choice: lexical variables,
a module system, closures, objects, all the kaboodle.

regards
- -- tomás
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