Re: perl scripting help

[kcott]

G'day ejm20,

Welcome to the Monastery.

I'm not entirely sure what your ultimate goal is here. You wrote "create a perl script in bash" which I find confusing. It seems to me that you could put your bash commands in a bash script and run that from an xterm (or equivalent).

Having said that, and based on the code you've managed so far, perhaps you're after something like this:

#!/usr/bin/env perl

use strict;
use warnings;
use autodie ':all';

my @commands = (
    'set -vx',
    "cd $ENV{HOME}",
    'date',
    'pwd',
    '/usr/bin/bash -i',
);

system qw{/usr/bin/xterm -e}, join ';', @commands;

When I run that, it pops up an xterm window containing:

+ cd /home/ken
+ date
Sat, 29 May 2021 10:44:54
+ pwd
/home/ken
+ /usr/bin/bash -i

ken@titan ~
$

I can now type more commands into that xterm window. It shuts down normally with exit or Ctrl-D.

One thing to note is that the Perl script (which I called pm_11133222_xterm.pl) will block until the xterm window closes. If that's an issue, you can run it in the background.

This starts the xterm and returns my normal prompt:

ken@titan ~/tmp
$ ./pm_11133222_xterm.pl &
[1] 2182

ken@titan ~/tmp
$

After closing the xterm and hitting enter:

ken@titan ~/tmp
$
[1]+  Done                    ./pm_11133222_xterm.pl

ken@titan ~/tmp
$

You may, of course, already know how to do that.

I didn't think I had gnome-terminal but apparently I do. I'm running Cygwin 3.2.0 (on Win10) so I no doubt got it via some package. I don't have a manpage for it; I found gnome-terminal(1); it says "gnome-terminal is designed to emulate the xterm program ..." but simply replacing xterm with gnome-terminal resulted in various warning and error messages. I got it to run by replacing the last line of script above with:

system qw{/usr/bin/gnome-terminal -- /usr/bin/bash -c}, join ';', @com
+mands;

This now popped up a window with the same initial content as the xterm window described above; subsequent interaction also worked the same. There were, however, two differences: the Perl script did not block; and, I got this warning:

** (gnome-terminal:2292): WARNING **: Error retrieving accessibility b
+us address: org.freedesktop.DBus.Error.NoReply: Message recipient dis
+connected from message bus without replying

An internet search for that message got quite a few hits. Here's a couple of workarounds to remove the warning:

$ NO_AT_BRIDGE=1 ./pm_11133222_gnome.pl

$ ./pm_11133222_gnome.pl 2> /dev/null

As I don't use gnome-terminal — fairly obviously as I only just found that I had it — I wasn't particularly interested in delving into this further. If you encounter the same problem and identify a genuine fix (as opposed to a workaround) please share as it may be useful to others in the future.