I have been using the following code logic for years to process command line args but just came across a case where it was clobbering @ARGV and causing trouble: 

my $arg;
my $argcount = 0;
my $debug = 0;
my $infile;

while (@ARGV) {
    $arg = shift @ARGV;
    if ($arg =~ /-d/) {
        $debug = 1;
    } elsif ($argcount == 0) {
        $infile = $arg;
    }
}

[download]

The code in question that I was trying to write was doing a "while (<>)" and trying to read a filename specified on the command line but @ARGV had been "emptied" in my earlier arg script. But, this time I was not explicitly opening the file, rather trying to rely on the <> automatic processing mechanism.

I was wondering if there was a better way to do this to avoid this problem. I know that some options include the getopts stuff but I tried these several years ago and they were very clunky and difficuly to manage, IMHO.

In reply to getting args without clobbering @ARGV by bfdi533

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.