Beefy Boxes and Bandwidth Generously Provided by pair Networks
Don't ask to ask, just ask
 
PerlMonks  

Calling and interacting with external executable

by verity (Initiate)
on Apr 25, 2012 at 18:33 UTC ( #967141=perlquestion: print w/ replies, xml ) Need Help??
verity has asked for the wisdom of the Perl Monks concerning the following question:

I have an executable that I need to call from my Perl script. It is pretty simple when run from the command line:

~$:/path/executable "Here is the script. Please choose option 1 or 2" 1 "Thank you. Please provide the input file name:" myInputFile.txt (script runs and output file appears in the directory) ~$:

I can't figure out how to supply the requested information from within the Perl script.

#I have tried my $program = "path-to-executable"; system($program); #The script hangs here until I manually enter the re +quested info at the command line system("1"); system("myInputFile.txt"); #Have also tried my $program = "path-to-executable"; my $i = `$program`; #Script hangs here and nothing appears on the comm +and line at all $i = `1`; $i = `myInputFile.txt`;

I have even tried adding sleep() commands but that does not fix the problem. Is there a way to let my script know it needs to keep talking to the executable?

Comment on Calling and interacting with external executable
Select or Download Code
Re: Calling and interacting with external executable
by toolic (Chancellor) on Apr 25, 2012 at 19:04 UTC
    Maybe you could use Expect (untested):
    use warnings; use strict; use Expect; my $command = 'path-to-executable'; my $exp = Expect->new(); $exp->raw_pty(1); $exp->spawn($command) or die "Cannot spawn $command: $!\n"; $exp->send("1\n"); $exp->send("myInputFile.txt\n"); $exp->soft_close();
Re: Calling and interacting with external executable
by thundergnat (Deacon) on Apr 25, 2012 at 19:20 UTC

    Can you pipe the selection to the executable?

    system( qq{ echo 1\n | $program });
Re: Calling and interacting with external executable
by 2teez (Priest) on Apr 25, 2012 at 20:34 UTC

    You can simply do it like this using system(...):

    use warnings; use strict; die "Usage: perl_script.pl path_to_exe_file.exe" unless defined $ARGV +[0]; my $file=$ARGV[0]; ## get the path to your executables from the CLI system($file); # interact with your exe #Or print "Enter your excutable path:"; chomp(my $path=<STDIN>); ## get path from your script system($path); # interact with your exe

    Try it, it works. Hope this helps

Re: Calling and interacting with external executable
by adler187 (Initiate) on Apr 25, 2012 at 20:55 UTC

    If you are calling an interactive program, that would be expected behavior using system or backticks. There is no way to interact with a program through those APIs, so you're program just sits there waiting for input.

    You can do a few things. You can pipe your answer to the program (if the program only expects 1 input) like so:

    system("echo $input_file_name | $program");

    If you're program asks multiple questions, then you will have to be more manual about it. You need to open a pipe to the program and print data to it, like you would a file. See open and the open tutorial

      Yes, open did it, thank you for the suggestion! Here is the code that worked:
      open(GERMS, "| $germline") || die "Could not call germline!\n"; print GERMS "1\n"; print GERMS "$map\n"; print GERMS "$ped\n"; print GERMS "out"; close GERMS;

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: perlquestion [id://967141]
Approved by toolic
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others cooling their heels in the Monastery: (18)
As of 2014-10-21 14:39 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    For retirement, I am banking on:










    Results (105 votes), past polls