<STDIN> detects only input after perl script is run.

tty1x has asked for the wisdom of the Perl Monks concerning the following question:

If I enter the alphabet h in together with the perl filname.pl command in Terminal ( perl filename.pl h ), it doesn't work.
It only works if I do it separately.
perl filename.pl
h

How do I make it work if I enter both together on the same line ? Thanks :)

#!/usr/bin/perl –w

chomp(my $user_value = <STDIN>);

if ($user_value eq "h") {
    print " hi \n";

}
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Comment on <STDIN> detects only input after perl script is run. Download Code

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Re: <STDIN> detects only input after perl script is run. by SuicideJunkie (Vicar) on May 03, 2013 at 15:36 UTC
`perl filename.pl h`is passing "h" as a command line parameter. You will find it in @ARGV `perl filename.pl h` [download] is providing no command line parameters, and sending "h" to STDIN	[reply] [d/l] [select]
Re^2: <STDIN> detects only input after perl script is run. by tty1x (Novice) on May 03, 2013 at 16:47 UTC
Ahh thanks for the `@ARGV` . That answers my question :)	[reply] [d/l]
Re: <STDIN> detects only input after perl script is run. by blue_cowdawg (Monsignor) on May 03, 2013 at 15:41 UTC
If you wanted to send an "h" to standard input you should invoke your script `echo "h" \| perl filename.pl` [download] also another thought: `#!/usr/bin/perl -w use strict; #damn fine idea my $user_value=<STDIN>; chomp $user_vaule;` [download] Peter L. Berghold -- Unix Professional Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg	[reply] [d/l] [select]
Re^2: <STDIN> detects only input after perl script is run. by tty1x (Novice) on May 03, 2013 at 16:49 UTC
Noted on `use strict` :)	[reply] [d/l]
Re: <STDIN> detects only input after perl script is run. by karlgoethebier (Abbot) on May 03, 2013 at 16:49 UTC
Perhaps you should think about using Getopt::Long or something similar? Regards, Karl «The Crux of the Biscuit is the Apostrophe»	[reply]


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