#!/opt/bin/perl
#
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#                                                                         #
#       Tool for re-generating old passwd file from new passwd file       #
#                                                                         #
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#                                                                         #
#    Version 1.0     -   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';
#
$self = $0;
#
if ($self =~ m!/([^/]+)$!) { $self = $1; }
#
$PWD_FILE = '/etc/passwd';
#
$pwd_file = $PWD_FILE;
#
# Get and check command line options:
#
while (@ARGV)
{
    $_ = shift;
    if    (/^-p$/)    { $pwd_file = shift; }
    elsif (/^-p\S+$/) { $pwd_file = substr($_,$[+2); }
    elsif (/^-\?$/)   { $help = 1; }
    elsif (/^-h$/)    { $help = 1; }
    else              { $error = 1; unless (defined $option) { $option = $_; } }
}
#
# Was help requested?
#
if ($help)
{
    print <<"@@";

Usage:  $self  [ <options> ]*      where <options> is one of the following:

  -p <pwd_file>   specifies the name of the passwd file
                  (default is '$PWD_FILE')

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

@@
    exit;
}
#
# Unknown option encountered?
#
if ($error)
{
    die
        "Error: Unknown option '$option' encountered!\n",
        "Enter '$self -h' for help.\n";
}
#
# Does the input file exist?
#
unless (($pwd_file ne "") && (-f $pwd_file))
{
    die "Error: Can't find file '$pwd_file'!\n";
}
#
# Prepare output filename:
#
$out_file = "$pwd_file.$self";
#
# Process input file:
#
open(IN_FILE, "<$pwd_file") || die "Can't open '$pwd_file': $!\n";
open(OUT_FILE, ">$out_file") || die "Can't write '$out_file': $!\n";
#
while (<IN_FILE>)
{
    chop;
    undef @field;
    @field = split(/:/, $_, 10);
    $field[$[+2] %= 1000;
    $field[$[+3] %= 1000;
    $_ = join(':', @field);
    print OUT_FILE $_, "\n";
}
#
close(IN_FILE);
close(OUT_FILE);
#
# Print acknowledgement:
#
printf("\n'%s' %s\n\n", $self, $version);
printf("Input file      = '%s'\n",   $pwd_file);
printf("Output file     = '%s'\n\n", $out_file);
#
# Done.
#