Action based on Character recieved from STDIN

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

Dearest Monks and Friends, Is there a way to to detect a character typed in STDIN without having pressed the RETURN key...And then take an action if that character is detected. I have a

while(<STDIN>) { }
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loop and i can enter input and process the input fine as long as the RETURN key is pressed... but what i'd really like to do is listen for a particular character to be typed at STDIN and then call a subroutine without having pressed the RETURN key at all. for Example I'd like to listen for the character `%` in some text entered at STDIN , say for e.g. `Hello %` and without pressing the RETURN key, call a subroutine since `%` was detected. I'd really, really appreciate any input on this. I'm really new to perl and thus far it has been good learning this amazing language, but i still need some help around the tricky bends, i hope you monks can guide me and show me the path to enlightenment ;).Thanks a lot in advance.

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Re: Action based on Character recieved from STDIN
by Plankton (Vicar) on Aug 30, 2004 at 21:57 UTC

bash-2.05b$ cat readkey.pl
#!/usr/bin/perl
use Term::ReadKey;
 
ReadMode 4; # Turn off controls keys
while (not defined ($key = ReadKey(-1))) {}
print "Get key $key\n";
ReadMode 0; # Reset tty mode before exiting
bash-2.05b$ ./readkey.pl
Get key 7
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TermReadKey

Plankton: 1% Evil, 99% Hot Gas.

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Re: Action based on Character recieved from STDIN
by Prior Nacre V (Hermit) on Aug 31, 2004 at 10:42 UTC

Something like this:

[ ~/tmp ] $ perl -wle 'use strict; { local $/ = \1; while (<>) { print
+ "Char: ", $., " is ", $_ } }'
qwerty
Char: 1 is q
Char: 2 is w
Char: 3 is e
Char: 4 is r
Char: 5 is t
Char: 6 is y
Char: 7 is 

[ ~/tmp ] $
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Update: See this excellent article which discusses the special variables used here.
Also note that the 'l' in -wle sets $\.

Regards,

PN5

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