Thanks a lot for your time!
I have 2 questions:
a) The code you kindly provided should be in 2 separate programs? I put it in one perl script, correct?
b) The old program I need to run has its executable in /usr/local/bin. Will the script need me to specify its full path?
I tried what you wrote and returned

enter file name  (you must specify the file name and press Enter)
Test.file
do you want to specify another file name (Y/N) (you must enter N in mo
+st cases and press Enter)
N
enter name for output file (you must specify a name for the output fil
+e, eg ttt and press Enter)
Result.file
reading Test.file; writing Result.file
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I suppose it didn't execute the external program, right? I used your code, like:

#! perl -slw
use strict;

print "enter file name  (you must specify the file name and press Ente
+r)";
chomp( my $infile = <STDIN> );

print "do you want to specify another file name (Y/N) (you must enter 
+N in most cases and press Enter)";
chomp( my $another = <STDIN> );

print "enter name for output file (you must specify a name for the out
+put file, eg ttt and press Enter)";
chomp( my $outfile = <STDIN> );

print "reading $infile; writing $outfile";

exit 99;

my $progname = '/usr/local/bin/simpa96';  #--->this is the name of the
+ external program I need to pass the parameters to
my $pid = open CMD, '|-', $progname or die $!;

print CMD 'myInfile';
print CMD 'N';
print CMD 'myOutfile';

close CMD;

waitpid $pid, 0;

print "$progname ended: status: ", $? >>8;
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