Re: How do I get a windowlist to STDOUT?

[Rod Nussbaumer]

Aaron Griffin wrote:
> On 1/3/06, Robert Blackwell <address@hidden> wrote:
>
> > I have been digging around to find a nice way to output the windowlist to
> > STDOUT but have not seen an easy solution.
> >
> > I would like to be able to do something like this
> >
> > screen -X windowlist > windows.txt
>
>
> I've been looking for something similar with the paste command (if
> that's the right name) - so "screen -X paste" will dump the current
> copy buffer.  I don't think any of the commands actually output to
> stdout when run from the command line.  Might be a nice thing to hack
> in though.

I think this perl subroutine does what you are trying to accomplish. 
Note that it does require screen to be setuid root, and obviously it 
runs 'outside' of screen itself.

I use this as part of a Tk GUI that allows our users to select from a 
menu of available multi-user sessions. There is a bit of Perl/Tk code in 
here that reflects this. Maybe this is helpful to someone.

I hope this makes it through without being destroyed by word-wrap.


#----------------------------------------------------------

sub refreshScreenList {

        #
        #       GNU screen stores it's list of active screen sessions in the
        #       /tmp/screens/S-* directory tree. We use the directory names to
        #       see which users *potentially* have screens alive.  Only the 
setuid
        #       screen program can see inside the directory tree, so we call
        #       it to do the work, once in each subdirectory.
        #
        opendir( SCREENS, "/tmp/screens" );
        my @screensDir = readdir SCREENS;
        closedir SCREENS;
        
        #
        #       Blank the list, then rebuild it
        #
        $screenList -> delete( 0, 'end' );
                        
        #
        #       Scan /tmp/screens/S-* for all users' screen sessions
        #
        foreach my $dir ( @screensDir ){
                $dir =~ s/^S-//;
                # print $dir,"\n";
                
                #
                #       Get screen to look into the directroy, and grab what it 
says.
                #
                open( SCREENLIST, "screen -S ".$dir."/ -list |" );
                my @screens = <SCREENLIST>;
                close( SCREENLIST );

                #
                #       Parse the output from screen, looking for a report of a 
live screen
                #
                foreach my $screen ( @screens ){

                        # Matching '1234.Any screen description'
                        if( $screen =~ /^\s+[0-9]+\./ ){
                                my $scr = $screen;

                                if( $scr =~ m/\([^)]+\)/ ){
                                        chomp $scr;
                                        $scr =~ s/\([^)]+\)//g;         # 
remove attachment status text
                                        my $status = $&;            # save 
status info
                                        $scr =~ s/^\s//g;               # trim 
leading and trailing spaces
                                        $scr =~ s/\s$//g;               #
                                        
                                        #
                                        #       Compose string to put into list 
widget
                                        #
                                        my $listItem = $scr."   ".$status."   
".$dir;
                                        $screenList -> insert( 'end', $listItem 
); # Append to list widget.
                                }
                        }
                }
        }
}

#----------------------------------------------------------


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Rod Nussbaumer,
Electronics Development Group, TRIUMF
Vancouver, Canada.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~