How to check a executable's status while running it.

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

Hi I am trying to run an executable by passing the name of exe with all the parameters to a subroutine. I don't have any idea how to check the status in perl. I am not sure about system() and exec() as they won't be returning the output. The code in vbscript is

Function ExecSyncStep(stepName)
    Dim WshShell, oExec
    Set WshShell = CreateObject("WScript.Shell")

    Set oExec = WshShell.Exec(stepName)
    Dim ouputStream
    ouputStream = ""
    Do While oExec.Status = 0
        Do While Not oExec.StdOut.AtEndOfStream
           ouputStream = ouputStream & oExec.StdOut.ReadAll
                Loop
         WScript.Sleep 100
    Loop
    Do While Not oExec.StdOut.AtEndOfStream
       ouputStream = ouputStream & oExec.StdOut.ReadAll
    Loop
    Set ExecSyncStep = oExec
End Function
[download]

I came up with this

#Returns the status object of the sync process
    $oExec;
    
    $oExec = system($stepName);
    $ouputStream = "";
    
    while($? eq 0){
        Do While Not oExec.StdOut.AtEndOfStream
           ouputStream = ouputStream & oExec.StdOut.ReadAll
        Loop
         sleep 100;
    }
    Do While Not oExec.StdOut.AtEndOfStream
       ouputStream = ouputStream & oExec.StdOut.ReadAll
    Loop
    #WScript.StdOut.Write ouputStream

    return $oExec;
}
[download]

Please advise.

Comment on How to check a executable's status while running it. Select or Download Code

Replies are listed 'Best First'.
Re: How to check a executable's status while running it. by dragonchild (Archbishop) on Apr 18, 2005 at 19:02 UTC
system() will set the return status in $?. Check it out. :-) My wife's blog	[reply]
Re^2: How to check a executable's status while running it. by ikegami (Patriarch) on Apr 18, 2005 at 19:25 UTC
It looks like the snippet checks whether a child is still running (by checking if the pipe is still open). `system` doesn't run a child in parallel, so your suggestion would help. It seems to me the solution would involve `fork`+`exec` (not recommended for Windows), `system 1, ...` (undocumented? Windows only), Win32::Process (Windows only), IPC::Open2, IPC::Open3, IPC::Run or IPC::Run3, but not `system`.	[reply] [d/l] [select]
Re^2: How to check a executable's status while running it. by Nesh (Beadle) on Apr 18, 2005 at 19:20 UTC
I came up withj this `#Returns the status object of the sync process $oExec; $oExec = system($stepName); $ouputStream = ""; while($? eq 0){ Do While Not oExec.StdOut.AtEndOfStream ouputStream = ouputStream & oExec.StdOut.ReadAll Loop sleep 100; } Do While Not oExec.StdOut.AtEndOfStream ouputStream = ouputStream & oExec.StdOut.ReadAll Loop #WScript.StdOut.Write ouputStream return $oExec; }` [download] Does this look right? But system won't return the output...	[reply] [d/l]
Re^3: How to check a executable's status while running it. by dragonchild (Archbishop) on Apr 18, 2005 at 19:28 UTC
`open( CMD, "$command \|" ) or die "Cannot open $command: $!\n"; while ( defined( my $line = <CMD> ) ) { # Do stuff with $line which is the output from $command } close CMD;` [download] Or, ikegami has a list of number of good modules that do similar things. My wife's blog	[reply] [d/l]