How do I start two programs without waiting for first one to be finished ?

[Anonymous Monk]

How do I start two programs without waiting for first one to be finished ?

Originally posted as a Categorized Question.

[runrig]

Fork them and run in the background:

system "( sleep 10; ls -l ) &";

Or use fork() explicitly:

if ( $pid = fork ) {
    # this is the parent
}
elsif ( defined $pid ) {
    # this is the child
    system "myprogram";
}
else {
    die "can't fork: $!";
}

[tye]

system( 1, "first" );  # Won't wait.
system( "second" );    # Will wait.

This is could be very portable though it also still appears to be mostly undocumented. ):

Update: I posted this long ago and later learned that system(1,...) was never allowed to work except on Windows (and OS/2, for which it was originally written). Any documentation on it appears to be relegated to perlport.

     - tye

[Anonymous Monk]

On Windows, I use this to launch one program and not wait, and then another with waiting.

use Win32::Process;

my $path = "C:\\mydirectory\\myprogram.exe";

Win32::Process::Create(
  $Process,
  $path,
  "myprogram",
  0,
  NORMAL_PRIORITY_CLASS,
  "."
)
or die "Can't Create - $!";

chdir "c:\\Program Files\\CoolRuler";
system "coolruler.exe";

[walto]

Linux:  system "first &";
Windows:  system "start /b first";
Both start first in background.