#!/opt/bin/perl
#
###########################################################################
#                                                                         #
#  Tool for copying the UIDs (GIDs) from one passwd-file (group-file) to  #
#  another.                                                               #
#                                                                         #
###########################################################################
#                                                                         #
#    Version 1.0     -   Written 14.04.95 by Steffen Beyer                #
#    Version 1.0.1   -   Written 15.04.95 by Steffen Beyer                #
#    Version 1.0.2   -   Written 04.05.95 by Steffen Beyer                #
#                                                                         #
###########################################################################
#                                                                         #
#    Copyright (C) 1995 by software design & management GmbH & Co. KG     #
#                                                                         #
###########################################################################
#
# Some important default settings...
#
$version = 'version 1.0.2';
#
$self = $0;
#
if ($self =~ /^.*\/([^\/]+)$/) { $self = $1; }
#
# Display usage if tool was called without parameters:
#
if (@ARGV == 0) { $help = 1; }
#
# Get and check command line options:
#
while (@ARGV)
{
    $_ = shift;
    if    (/^-\?$/)   { $help = 1; }
    elsif (/^-h$/)    { $help = 1; }
    elsif (/^-.*/)    { $error = 1; unless (defined $option) { $option = $_; } }
    else              { push(@filename, $_); }
}
#
# Was help requested?
#
if ($help)
{
    print <<"@@";

'$self' $version

Usage:  $self  [ <options> ]*  <filename_1>  <filename_2>

where <options> is one of the following:

  -h                      produces this help screen
  -?                      produces this help screen

  Copies the UIDs (GIDs) from the passwd-file (group-file) <filename_1>
  to the passwd-file (group-file) <filename_2> for the corresponding
  users (groups).

@@
    exit;
}
#
# Unknown option encountered?
#
if ($error)
{
    die
  "Error: Unknown option '$option' encountered!\nEnter '$self -h' for help.\n";
}
#
# Are there two filenames specified?
#
if (@filename != 2)
{
    die "Error: You must specify two filenames!\nEnter '$self -h' for help.\n";
}
#
# Extract the two filenames:
#
$file_a = $filename[$[];
$file_b = $filename[$[+1];
#
# Do the specified files exist?
#
unless (($file_a ne "") && (-f $file_a))
{
    die "Error: Can't find file '$file_a'!\n";
}
unless (($file_b ne "") && (-f $file_b))
{
    die "Error: Can't find file '$file_b'!\n";
}
#
# Scan first file:
#
open(FILE_A, "<$file_a") || die "Can't open '$file_a': $!\n";
#
while (<FILE_A>)
{
    chop;
    ($name, $passwd, $id) = split(/:/);
    if ($id_name{$name} ne "")
    {
        if ($id == $id_name{$name})
        {
            warn "Warning: Name '$name' in file '$file_a' is not unique!\n";
        }
        else
        {
            die "Error: Name '$name' in file '$file_a' is not unique!\n";
        }
    }
    else
    {
        $id_name{$name} = $id;
    }
}
#
close(FILE_A);
#
# Prepare output filename:
#
$file_c = "$file_b.$self";
#
# Scan second file:
#
open(FILE_B, "<$file_b") || die "Can't open '$file_b': $!\n";
open(FILE_C, ">$file_c") || die "Can't write '$file_c': $!\n";
#
while (<FILE_B>)
{
    chop;
    undef @field;
    @field = split(/:/, $_, 10);
    $name = $field[$[];
    if ($id_name{$name} ne "")
    {
        $field[$[+2] = $id_name{$name};
    }
    else
    {
        warn "Warning: No new ID for name '$name' of file '$file_b'!\n";
    }
    $_ = join(':', @field);
    print FILE_C $_, "\n";
}
#
close(FILE_B);
close(FILE_C);
#
# Print acknowledgement:
#
printf("\n'%s' %s\n\n", $self, $version);
printf("Input file (source) = '%s'\n",   $file_a);
printf("Input file (target) = '%s'\n",   $file_b);
printf("Output file         = '%s'\n\n", $file_c);
#
# Done.
#