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I installed DOSBOX on my computer along with QBASIC.EXE which is Microsoft's QBasic 1.1 IDE from the old DOS days. So, I put a little icon on my Linux desktop, and when I double click it, it automatically launches QBASIC.EXE on Linux. For this, I had to install perl and dosbox, of course. I wrote a perl script that modifies the dosbox config file, changing it slightly to enter autoexec commands once it loads. This way, it automatically mounts drive c and goes to the appropriate directory and launches a program.

First, I am going to include the Linux desktop file, which I call qb11.desktop :

[Desktop Entry]
Name=QBasic 1.1
Exec=/usr/bin/perl /home/owner/Desktop/rundos.pl "C:\HOME\OWNER\DESKTO
+P" "C:\HOME\OWNER\BIN\DOS\QBASIC.EXE"
Icon=/home/owner/.icons/qb.png
Comment=Run Microsoft QBasic 1.1
GenericName=QBASIC IDE
Type=Application
[download]

On a Linux computer, the existence of this file creates a clickable desktop icon. When the user double-clicks the icon, whatever follows the Exec= line will get executed.

I also created a directory called /home/owner/.icons which are full of various custom icons I use. And I put qb.png file there, which is a nice QBasic logo. And I created a directory called /home/owner/BIN, which holds every executable that is not native to Linux.

Now, here is the perl script that modifies the dosbox config file. It's really simple:

#!/usr/bin/perl -w

# rundos.pl
#
# This program modifies the dosbox configuration file so that when you
+ type 'dosbox' in the
# terminal, it automatically launches a program. Usage: perl rundos.pl
+ <workdir> <dosprogram>
# The workdir must be a full path using backslash as the separator and
+ must be enclosed with
# double quotes. The dos program must include the full location of the
+ program and the
# program name the same way.. Make sure that the path includes only 8+
+3 filenames and the
# program itself also has a name that is 8+3 length. (Here "8+3" means
+ the file name is
# max 8 letters long, and the extension is 3 max letters long.)
#
# It does not matter whether the first and second arguments are in upp
+ercase or lowercase,
# because these will be used inside dosbox. In a dos environment, the 
+directory and program
# names can be in upper or lower case, and it's all the same. But it i
+s important to always
# enclose the first and second arguments with double quotes.
#
# When you run this program without any arguments, "perl rundos.pl" it
+ will remove the program
# launcher from the dosbox config file, so when you type "dosbox" in t
+he terminal,
# it will let you decide what you want to do...
#
# When you run this program with just one argument, "perl rundos.pl \h
+ome\owner\dos" it
# will launch dosbox in that directory.
#
# Example for running with two arguments:
#    perl rundos.pl "\home\owner\dos" "\home\owner\dos\qbasic.exe"

use strict;
use warnings;

-e '/usr/bin/dosbox' or die "\nError: /usr/bin/dosbox is not found. Pl
+ease install it.\n";

my $WORKDIR = (@ARGV > 0) ? $ARGV[0] : '';
my $DOSPROG = (@ARGV > 1) ? $ARGV[1] : '';
my $HOMEDIR = $ENV{HOME};

# Read this file:
my $F = $HOMEDIR . '/.dosbox/dosbox-0.74-3.conf';
-f $F or die "\nError: Dosbox configuration file not found - $F !!!\n\
+n";

# Read the config file's contents:
@ARGV = ($F);
my @LINES = <>;

# Find the line that begins with [autoexec]
my $FOUND = 0;
for (my $i = 0; $i < @LINES; $i++)
{
  $LINES[$i] =~ tr|\r\n||d;
  if ($FOUND) { $LINES[$i] = ''; }
  if (index($LINES[$i], '[autoexec]') >= 0) { $FOUND = $i; }
}
if ($FOUND) { splice(@LINES, $FOUND); }   # Delete it and everything t
+hat follows...
else { die "\nError: Dosbox config file doesn't contain [autoexec] sec
+tion.\n"; }

if (length($WORKDIR) && length($DOSPROG))
{
  push(@LINES, '[autoexec]');
  push(@LINES, 'mount c /');
  push(@LINES, 'c:');
  push(@LINES, "cd $WORKDIR");
  push(@LINES, 'cls');
  push(@LINES, $DOSPROG);
  push(@LINES, 'exit');
}
elsif (length($WORKDIR))
{
  push(@LINES, '[autoexec]');
  push(@LINES, 'mount c /');
  push(@LINES, 'c:');
  push(@LINES, 'cd ' . $WORKDIR);
  push(@LINES, 'dir /w');
}
else
{
  push(@LINES, '[autoexec]');
  push(@LINES, 'ver');
}

# Save modified config file.
open my $fh, '>', $F or die "\nError: Cannot update to $F !!!\n\n";
print $fh join("\n", @LINES), "\n";
close $fh;

# Launch dosbox.
exec('dosbox');
[download]

In reply to Icon on my Linux desktop to launch a DOS program by harangzsolt33

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