These various getopt things parse tokens on the command line.

In your case, perhaps Getopt::Std will be just fine. This not to say that that other suggestions aren't fine also. 

use Getopt::Std;
my %opts;

die "Usage $0 -m or -M #1 #2 #3..." if (!getopts( "mM", \%opts)
    || @ARGV !=0 || keys %opts != 2);
CalculateMean()   if $opts{m}; #@ARGV has just #1 #2 #3 ...now.
CalculateMedian() if $opts{M};

[download]

getopts::Std take a string and a ref to a hash as args. The magic of getopts in its various flavors is that it removes the option and the parameter (if any) from @ARGV.

There is a syntax for this: "mf:" means that "-m" doesn't have an arg, but that "-f" does, like someprogram -m -f filename 1 2 3. In this case the %opts hash will have keys of "m" and "f". The value of $opts{m}=1, the value of $opts{f} = 'filename' and @ARGV = (1,2,3).

You can have things like -a -f filename 1 2 3 4 or -f filename -a 1 2 3 4. Of course if somebody types in: -a -f 1 2 3 4 filename, you have to figure out that "1" isn't a filename. Anyway getopts looks for essentially space separated tokens, -3 like +3. That's the way that a C program would get the args.

I hope this helped.

In reply to Re^3: Usage of flags in scripts by Marshall
in thread Usage of flags in scripts by jordandanford

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.