Re: Process ID of qx

Let's not forget that the process no longer exists after the qx completes. But anyway, you could do this using open instead of qx, e.g.: (updated to correct pipe direction)

use POSIX ":sys_wait_h";

# e.g.:
my ($pid, $listing) = pidqx( "ls" );

sub pidqx { # returns pid + the usual backtick result
    my $pid = open my $ph, "$_[0] |" or die "$!: $_[0]";
    local $/ = undef();
    my $backtick = <$ph>;
    close $ph;
    waitpid $pid, 0; 
    return ( $pid, $backtick );
}
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-M

Free your mind

Comment on Re: Process ID of qx Download Code

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Re^2: Process ID of qx by kyle (Abbot) on Mar 05, 2007 at 14:16 UTC
`my $pid = open my $ph, "\| $_[0]" or die "$!: $_[0]";` Your open is opening for write instead of read. The command's output goes to STDOUT instead of to your variable. Try this: `sub pidqx { # returns pid + the usual backtick result my ( $cmd ) = @_; my $pid = open my $ph, '-\|', $cmd or die "$!: $cmd"; local $/ = undef(); my $backtick = <$ph>; close $ph; return ( $pid, $backtick ); }` [download] Also, you don't have to wait for the command to finish because close does that for you.	[reply] [d/l] [select]

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Re^2: Process ID of qx
by kyle (Abbot) on Mar 05, 2007 at 14:16 UTC

my $pid = open my $ph, "| $_[0]" or die "$!: $_[0]";

Your open is opening for write instead of read. The command's output goes to STDOUT instead of to your variable. Try this:

sub pidqx { # returns pid + the usual backtick result
    my ( $cmd ) = @_;
    my $pid = open my $ph, '-|', $cmd or die "$!: $cmd";
    local $/ = undef();
    my $backtick = <$ph>;
    close $ph;
    return ( $pid, $backtick );
}
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Also, you don't have to wait for the command to finish because close does that for you.

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