CODEWITHSUNDEEP
perlmultiprocessing
int80h
int80h

Reputation: 265

How to spawn other programs within perl script and immediately continue Perl processing?

How to spawn other programs within perl script and immediately continue Perl processing (instead of halting until the spawned program terminates) ? Is it possible to process the output coming from the spawned program while it is running instead of waiting it to end?

Upvotes: 1

Views: 2210

Answers (2)

pirhac
pirhac

Reputation: 927

To run a program in the background and "continue going" all you have to do is add "&" at the end of the command (I'm assuming you are using Linux). example:system("command &"); note that system("command", "arg1", "&"); will NOT work, since it will pass the "&" to the command and not to the shell. You can simply print the output of a command by doing: print system("command");

Upvotes: 1

Martijn
Martijn

Reputation: 1620

You can use open for this (to run the program /bin/some/program with two command-line arguments):

open my $fh, "-|", "/bin/some/program", "cmdline_argument_1", "cmdline_argument_2";
while (my $line = readline($fh)) {
    print "Program said: $line";
}

Reading from $fh will give you the stdout of the program you're running.

The other way around works as well:

open my $fh, "|-", "/bin/some/program";
say $fh "Hello!";

This pipes everything you write on the filehandle to the stdin of the spawned process.

If you want to read and write to and from the same process, have a look at the IPC::Open3 and IPC::Cmd modules.

Upvotes: 6

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