Beefy Boxes and Bandwidth Generously Provided by pair Networks RobOMonk
The stupid question is the question not asked
 
PerlMonks  

Re: bash vs perl

by naChoZ (Curate)
on Jan 11, 2008 at 15:12 UTC ( #661894=note: print w/ replies, xml ) Need Help??


in reply to bash vs perl

Actually it's very easy to use getopts from bash the way you're asking. This example would handle myscript.sh -a -b testval -c anotherval with the options a, b, and c.

while getopts ab:c: FOO do case ${FOO} in a) BAR="somevalue" ;; b) BAR="${OPTARG}" ;; c) BAZ="${OPTARG}" ;; \?) echo "<some help text>" exit 1 ;; esac done

The getopts ab:c: means that it's looking for -a, -b, -c and the colon after the b and the c means it expects a value to be specified for those params.

So, while it's obviously not that difficult, it's also very, very limited and is vastly outstripped by perl modules like Getopt::Long. For example, you can only use single letters for your options. Sure, that's 24 available options which is plenty for most scripts, but what if you wanted to specify something like -min and -max. Suddenly you have to remember what letter you've assigned to what functions and it quickly becomes unwieldly.

Check out my brief Getopt::Long example I posted over here recently.

--
naChoZ

Therapy is expensive. Popping bubble wrap is cheap. You choose.


Comment on Re: bash vs perl
Select or Download Code
Re^2: bash vs perl
by leocharre (Priest) on Jan 11, 2008 at 16:00 UTC

    Thank you for the example. Indeed when I saw these kinds of scripts to read three options, that's what made me gag.

    That's a *lot* of typing for three options. As I'm sure you know, compared to perl's 3 (three, tres) lines:

    use Getopt::Std; my $o={}; getopts('ab:c:defghijklmnop',$o); # map { printf "%s %s\n", $_, $o->{$_} } keys %$o;

    I disagree that single letter options are limited, in fact I throw a tantrum about that.
    '--min' in one cli app may be '--minimum' in another, we *know* that. So long notation doesn't really improve anything more then legibility, at least for the occasional user. Yes, yes.. then there are monsters like imagemagick convert.. good point, those need long.

    The only thing we can ever really be sure of is that hopefully us who code actually reserve -h for help, and that the documentation exists.

    The documentation is the authority for an interface. Some basic rules alway, yes.. options before file lists.. -h for help, -v for version, etc.. The user should *never* have to remember anything. Ever. -h, man, and info will tell them whatever they need to know.
    By the way, it's not 24, it's 52 or so, caps ! And I use them. And I document them. :-)

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://661894]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others romping around the Monastery: (4)
As of 2014-04-20 19:08 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    April first is:







    Results (486 votes), past polls