On Wed, 2005-04-13 at 12:32, Thomas BÃtzler wrote:
> Ramprasad A Padmanabhan <[EMAIL PROTECTED]> asked:
> > I want to write a perl script like "gnu less".
> >
> > My perl script accepts input on STDIN or filename(s) as arguments.
> > If both are missing it should print the error message. How do
> > I do this ?
>
> There is always input on STDIN - even a straight eof could be input,
> like in "cat empty_file | ramprasads_less". You should probably try
> and check for filename arguments and revert to STDIN processing if
> there are none, i.e.
>
> my @files;
>
> if( @ARGV ){
> @files = @ARGV;
> } else {
> @files = ("-");
> }
>
> foreach my $file (@files){
> # transparent gzip decompression
> $file = "/usr/bin/gzip -d < $file|" if $file =~ m/\.gz$/;
>
> open( IN, $file ) or die "Cam't open '$file': $!";
> # do something
> close( IN );
> }
>
> HTH,
> Thomas
That is perfectly ok .. but I require to print usage if there is no
input How do I do this ?
Thanks
Ram
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