Re^2: How to accept ARG from PIPE or STDIN?

If you wanted to do:

dosomething.pl myfile.txt
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You need to get the filename from the first element in @ARGV, the arguments array. You may also want to check out Multiple STDIN sources.

No. <> treats as a list of file names, and opens each of them in turn. <> only reads from STDIN if @ARGV is empty. In other words,

while (<>) {
  # do something with $_
}
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works for all of the following:

cat myfile.txt | dosomething.pl

dosomething.pl < myfile.txt

dosomething.pl myfile.txt
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Comment on Re^2: How to accept ARG from PIPE or STDIN? Select or Download Code

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Re^3: How to accept ARG from PIPE or STDIN? by monkfan (Curate) on Mar 17, 2005 at 03:16 UTC
But how about, if I want to use "die" command in this standard context? `open INFILE, "<$file" or die "$0: Can't open file $file: $!"; while (<INFILE>){ # do something with $_ }` [download] Does it still work? Regards, Edward	[reply] [d/l]
Re^4: How to accept ARG from PIPE or STDIN? by ikegami (Patriarch) on Mar 17, 2005 at 04:34 UTC
Then you can do something like: `my $file = $ARGV[0]; if (defined $file) { open(IN, "< $file") or die("Unable to open supplied argument: $!\n"); } else { IN = STDIN; } while (<IN>) { print($_); # do stuff }` [download] or with some magic: `my $file = @ARGV ? $ARGV[0] : '-'; open(IN, "< $file") or die("Unable to open input file: $!\n"); while (<IN>) { print($_); # do stuff }` [download] or the OO way: `use FileHandle; my $file = $ARGV[0]; my $fh_in; if (defined($file)) { $fh_in = FileHandle->new($file, 'r') or die("Unable to open supplied argument: $!\n"); } else { $fh_in = *STDIN{IO}; } while (<$fh_in>) { print($_); # do stuff }` [download]	[reply] [d/l] [select]