Redirect Unix Input Within Perl

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

I have a program "execopu -text" that can take input from a file "file.txt" and execute the data inside by doing: execopu -text < file.txt from a Unix command line.

"file.txt" looks like this:

cell
u
csno = 7
ccuoosmin_3g1x = ""
ccuoos_3g1x = ""
u
u
csno = 12
ccuoosmin_3g1x = ""
ccuoos_3g1x = ""
u
[download]

I want to automate the generation of the "file.txt" and execution of the script into one Perl script. How can I modify this script to "<" redirect the output generated by the "print" statements using the same method as the Unix "<" but do this within perl instead? Right now the sript below is having issues using the "open" command.

#!/usr/bin/perl

my @sitenumbers = (7,12);

open(EXECOPU, '| execopu -text')
or die("Can't run execopu: $!\n");

print EXECOPU "cell\n";

foreach my $site_number (@sitenumbers){

print EXECOPU <<"EOF";
u
csno = $site_number
ccuoosmin_3g1x = ""
ccuoos_3g1x = ""
u
EOF

}
[download]

Comment on Redirect Unix Input Within Perl Select or Download Code

Replies are listed 'Best First'.
Re: Redirect Unix Input Within Perl by ikegami (Patriarch) on Apr 20, 2005 at 14:36 UTC
The script provided already does exactly that. It can be proven by changing `open(EXECOPU, '\| execopu -text')` to `open(EXECOPU, '\| cat')` `$ cat 449609.pl #!/usr/bin/perl my @sitenumbers = (7,12); #open(EXECOPU, '\| execopu -text') open(EXECOPU, '\| cat') or die("Can't run execopu: $!\n"); print EXECOPU "cell\n"; foreach my $site_number (@sitenumbers){ print EXECOPU <<"EOF"; u csno = $site_number ccuoosmin_3g1x = "" ccuoos_3g1x = "" u EOF } $ perl 449609.pl cell u csno = 7 ccuoosmin_3g1x = "" ccuoos_3g1x = "" u u csno = 12 ccuoosmin_3g1x = "" ccuoos_3g1x = "" u` [download]	[reply] [d/l] [select]
Re: Redirect Unix Input Within Perl by polettix (Vicar) on Apr 20, 2005 at 14:41 UTC
awohld, why repeating node Auto Feeding Data to Unix Programs? Anyway, Right now the sript below is having issues using the "open" command: what are these issues? Is the open working? Does the script die, and what's the error message? Flavio (perl -e "print(scalar(reverse('ti.xittelop@oivalf')))") Don't fool yourself.	[reply]
Re^2: Redirect Unix Input Within Perl by awohld (Hermit) on Apr 20, 2005 at 18:00 UTC
The script was working fine after all, it was a syntax issue with the text generation. Can't have spaces besides the "=". Thanks for all the help!	[reply]
Re: Redirect Unix Input Within Perl by gellyfish (Monsignor) on Apr 20, 2005 at 14:36 UTC
What do you mean by "issues using the "open" command." ? If it is failing you should be getting a meaningful message from `$?`. Anyway if you want to capture the output of the program as well as piping to it's STDIN you probably want to look at the module IPC::Open2 which is standard with Perl. /J\	[reply] [d/l]
Re^2: Redirect Unix Input Within Perl by awohld (Hermit) on Apr 20, 2005 at 14:46 UTC
The "execopu" program is complaing about null fields and mask problems when I use the Perl script. I have no idea what those are because there's no documentation about that. But "execopu" is working usiung the "execopu -text < file.txt" method, but not with the Perl script. ???	[reply]