From: rsperko AT icaebc DOT com
Subject: Perl script to set up bash environment.
9 Dec 1996 20:28:52 -0800
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I have written a perl script for the win32 version of perl that 
converts envinronment variables over to unix type variables for bash,	
then resets the variables after leaving bash.  I should have posted 
this a while ago, but richardd AT cix DOT compulink DOT co DOT uk got my butt moving 
with his post.  I call it "shell.bat" and here is how it goes:

cut-------------------------------------------------------------------

@rem = '--*-Perl-*--';
@rem = '
@echo off
perl.exe c:\usr\bin\shell.bat %1 %2 %3 %4 %5 %6 %7 %8 %9 
goto endofperl @rem ';


# Set root dir
$ROOTDRIVE = "C";

# Set an array of variables to skip
@skip_vars = (
HOME,
MAKESTARTUP,
SHELL,
);

# Get the temp environment var
$tempdir = $ENV{'TEMP'};


# If temp wasnt set set it to default
if (! $tempdir)
{
    $tempdir = "$ROOTDRIVE:\\tmp";
}


# Copy the temp envir var for later
$tempsave = $ENV{'TEMP'};


#######################################################################
# REMEMBER! if you change these file names you need to change them
# after :endofperl as well!
$bashenv = "bashenv.bat";
$saveenv = "saveenv.bat";


# Open file handles to creat environment batch files for before and
# after bash runs
open (BASHENV, "> $tempdir\\$bashenv") 
 || die "ERROR: Couldn't open \"$tempdir\\$bashenv\": $!\n";
open (SAVEENV, "> $tempdir\\$saveenv") 
 || die "ERROR: Couldn't open \"$tempdir\\$saveenv\": $!\n";


# If comspec is set use it otherwise set a default
if ($ENV{'COMPSPEC'})
{
 $comspec = $ENV{'COMSPEC'};
}
else
{
 $comspec = "c:\\command.com";
}


# Get the environment from comspec
open (ENV, "$comspec /c set |")
 || die "ERROR: Couldn't get the environment from \"$comspec\": $!\n";


# Copy the environment to an array for easy parsing
@env = <ENV>;


# Process the environment
foreach $var_data (@env)
{
    chop $var_data;


    # Print the var as is to the save file
    print SAVEENV "set $var_data\n";

    # Break down the var and data
    ($var, $data) = ($var_data =~ /([^=]+)=(.*)/);

    if (grep(m#$var#, @skip_vars))
    {
 print BASHENV "set $var=$data\n";
 next;
    }

    # Unixify the paths
    $data =~ s/\\/\//g;

    # Remove quote marks
    $data =~ s/"//g;

#    # This is for Novell servers mapped drives, change the server\sys
#    to # F: if ($data =~ /server_name\/sys:/i) {
#        $data =~ s/server_name\/sys:/F:/ig;
#    }

    # If data contains a semi-colon assume it is a path
    if ($data =~ /\S+;\S+/)
    {
        # Clear the path variable
        $path = "";

        # Build an array consisting of path parts
        @path_dirs = split(/;/, $data);

        foreach $dir (@path_dirs)
        {
            # If $dir matches "X:" X being a letter, then must be a
            drive # letter, change it to gnu-win32 //X format
     if ($dir =~ /^[A-Za-z]:/)
            {
                $dir = &gnu_drive($dir);
            }

            # Now that we have the directory formatted correctly add
            it to # The path $path="$path$dir:";
        }

        # Replace $data with the $path we created
        $data = $path;
    }
    # If we got this far and match X: must be a drive letter by itself
    no # directory following elsif ($data =~ /[A-Za-z]:/) {
        $data = &gnu_drive($data);
    }

    # Print the variable and the data to bashenv file
    print BASHENV "set $var=$data\n";

}

# Add tempsave in DOS env format to $tempsave so we can use it later
print BASHENV "set TEMPSAVE=$tempsave\n";

# If $HOME isn't set assume it is H:
if (!($ENV{'HOME'}))
{
 print BASHENV "set HOME=H:\n";
}



#######################################################################
# gnu_drive takes a path and changes it from "X:\directory" to
# "//X/directory" for bash

sub gnu_drive
{
    # Keep variable safe and local
    local($path) = @_;
    local($drive, $dir);

    # if path matches "X:\directory" break it down.
    if ($path =~ /[A-Za-z]:\S+/)
    {
     ($drive, $dir) = ($path =~ /([A-Za-z]):(\S+)/);
    }
    # If path matches just "X:" take the drive and clear the dir
    elsif ($path =~ /^[A-Za-z]:$/)
    {
     ($drive) = ($path =~ /([A-Za-z]):/);
 $dir = "";
    }

    if ($drive =~ /$ROOTDRIVE/i)
    {
 $drive = "";
    }
    else
    {
 $drive = "//$drive";
    }

    # If dir does not start with "\" add it.
    if (!($dir =~ /^\//))
    {
        $dir = "/$dir";
    }

    # Give back the rewritten environment
    return "$drive$dir";
}


# That is all of the perl script!

__END__
:endofperl

@rem Now run that batch file at the end.

@rem Run the bashenv.bat file to reset the environment to bash style
@call %TEMP%\bashenv.bat

@rem Run bash
@c:\usr\bin\bash.exe

@rem Reset the environment to the original configuration
@call %TEMPSAVE%\saveenv.bat

cut-------------------------------------------------------------------

Make sure you have perl installed in your path and run this from the 
command line (I set up a short cut to it).  Change the ROOTDIR 
variable to the applicable drive letter, add variables that you do 
not want change to "skip_vars" and away you go.

I hope this helps some one.

Later,
Rick
-------------------------------------------------------------------
  o80808o                         | I know I am mad, I have always
  |-----|ri Deja Brew... We have  | been mad as most of us have.
  | | | | | all been beer before  | Yet you must explain why you 
  | | | |/                        | are mad... Even if you are not
  |_____|                         | mad.
  I_____I                         |                  -Pink Floyd
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