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From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: comp.lang.perl
Subject: Re: Perl STDIN and ARGV
Message-ID: <1991Jan28.194851.9307@convex.com>
Date: 28 Jan 91 19:48:51 GMT
References: <1991Jan28.083825.15064@sgitokyo.nsg.sgi.com>
Sender: usenet@convex.com (news access account)
Reply-To: tchrist@convex.COM (Tom Christiansen)
Organization: CONVEX Software Development, Richardson, TX
Lines: 28
Nntp-Posting-Host: pixel.convex.com

From the keyboard of kandall@sgitokyo.nsg.sgi.com (Michael Kandall):
:A common UNIX(tm) System utility usage is to process command line args,
:and if they are not present to process stdin.
:
:What's the standard paradigm for switching between these two in Perl?

Normally you do something like this:

    while (<>) {  # <> is magic
	# blah
    } 

This will read from the files on the command line, or stdin if none are
given, and will correctly interpret "-" as stdin in the midst of the
stream.  If you want to process leading -foo options, you can use one of
the getopts libraries:

    require 'getopts.pl';
    &Getopts('wxyza:b:') || &usage;

You mIhgt also use even the -s flag for simple things.  For really
sophisticated argument parsing, you might wish to roll your own.

--tom
--
"Hey, did you hear Stallman has replaced /vmunix with /vmunix.el?  Now
 he can finally have the whole O/S built-in to his editor like he
 always wanted!" --me (Tom Christiansen <tchrist@convex.com>)