The GECOS Phonebook in Perl - Now with bugfixes

Screenies of my GECOS Phonebook App in action

I wrote this over a period of 3 days in Perl.  It’s 252 lines of Perl code and it works great!  The “Office Phone” of 414-744-4609 is the number for the Lake Masonic Center, BTW.

Here are t3h codes:

#!/usr/bin/perl
use strict;
use warnings;

# phonebook.pl
# A script to build a phonebook from the data in the
# /etc/passwd GECOS field
#

# CHANGELOG
# 073:20100531:01 change conditional to a one-liner
# 091:20100531:02 change conditional to one-liner
# 184:20100531:03 change conditional to a one-liner
# 044:20100531:04 perl-ify the error handling
# 056:20100531:05 perl-ify the error handling
# 065:20100531:06 perl-ify the error handling
# 081:20100531:07 perl-ify the error handling
# 112:20100531:08 perl-ify the error handling
# 128:20100531:09 perl-ify the error handling
# 203:20100531:10 reverse direction of conditional
# 215:20100531:11 fix a whitespace issue with split(/ / ) that perltidy messed with

# OPTIONS
my $GROUPARG = "-g";

# Variables
my $groupname = "";
my $arg;
my $groupent;
my @groupdata;
my $groupmembers;
my @memberlist;
my @mpwent;

#my $isGID     = 0;
my $testfield  = 0;
my $groupfound = 0;

my @gecos;
my @phonebook;
my @phonebook_keys = (
    'Last Name',
    'First Name',
    'Unix Name',
    'Office',
    'Office Phone',
    'Home Phone',
    'E-mail address'
);
my %phonebookent =
  map { $_ => "" } @phonebook_keys;    # thanks to raldi@stackoverflow
my %columnwidths = map { $_ => length($_) + 4 } @phonebook_keys;

print "\n";

# Check for group on command line
foreach ( 0 .. $#ARGV ) {
    $arg = $ARGV[$_];
    if ( $arg eq $GROUPARG ) {

        # chek for next argument
        # 20100531:04 perl-ify the error handling
        die("$arg needs a group name")
          if ( $_ == $#ARGV );    # if we're at the last argument

        #		if ($_ == $#ARGV) { # if we're at the last argument
        #			# fail
        #			print STDERR "$arg needs a group name\n";
        #			exit 1;
        #		}

        $groupname = $ARGV[ ++$_ ];

        # 20100531:05 perl-ify the error handling
        die("$arg needs a group name")
          if ( length($groupname) < 1 );    # if we have an empty string

        #		if (length($groupname) < 1) { # if we have an empty string
        #			# fail
        #			print STDERR "$arg needs a group name\n";
        #			exit 1;
        #		}

        # 20100531:06 perl-ify the error handling
        die("$arg needs a group name")
          if ( substr( $groupname, 0, 1 ) eq '-' )
          ;    # if the next argument starts with a -
         #if (substr($groupname, 0, 1) eq '-') { # if the next argument starts with a -
         #	# fail
         #	print STDERR "$arg needs a group name\n";
         #	exit 1;
         #}

        #DEBUG print group
        #print "Group $groupname\n";
    }
}

# check if we got a group
if ( length($groupname) > 0 ) {

    # fetch the members of that group
    # 20100531:07 perl-ify the error handling
    open( GROUP_FH, "/etc/group" )
      or die("Couldn't open /etc/group");    # try to open /etc/group
        #if (!open(GROUP_FH, "/etc/group")) { # try to open /etc/group
        #	# fail if open() fails
        #	print STDERR "Couldn't open /etc/group\n";
        #	exit 1;
        #}

    # check if we have a GID or group name
    # 20100531:01 change conditional to a one-liner
    # regex for digit test from Graham Ellis of wellho.net
    $testfield = 2
      if ( $groupname =~ /^-?\d/ )
      ;    # regex for digit test from Graham Ellis of wellho.net

    # read in /etc/group, line by line, checking for the name or GID we want
    while ( $groupent = <GROUP_FH> ) {
        @groupdata = split( /:/, $groupent );

        if ( $groupdata[$testfield] eq $groupname ) {

            # we found it - read the members
            $groupfound   = 1;
            $groupmembers = $groupdata[3];
            chomp $groupmembers;

            # if we actually have members
            # 20100531:02 change conditional to one-liner
            @memberlist = split( /,/, $groupmembers )
              if ( length($groupmembers) > 0 );
        }

    }

    # 20100531:08 perl-ify the error handling
    die("Group $groupname not found in /etc/group")
      unless ($groupfound);    # if we didn't find the requested group
         #if (!$groupfound) { # if we didn't find the requested group
         #	# fail
         #	print STDERR "Group $groupname not found in /etc/group\n";
         #	exit 1;
         #}

}

else {

    # just fetch all entries in /etc/passwd
    my @pwdata;
    my $pwent;

    # 20100531:09 perl-ify the error handling
    open( PASSWD_FH, '/etc/passwd' ) or die("Unable to open /etc/passwd");

    #if (!open(PASSWD_FH, '/etc/passwd')) {
    #	# fail
    #	print STDERR "Unable to open /etc/passwd\n";
    #	exit 1;
    #}

    while ( $pwent = <PASSWD_FH> ) {
        @pwdata = split( /:/, $pwent );
        push( @memberlist, $pwdata[0] ); # push the username onto the memberlist
    }

    close PASSWD_FH;
}

# walk through the members list
my $member;

foreach $member (@memberlist) {

    #print $member . "\t"; #DEBUG

    my $name;
    my $passwd;
    my $uid;
    my $gid;
    my $quota;
    my $comment;
    my $gcos;
    my $dir;
    my $shell;
    my $expire;
    (
        $name,    $passwd, $uid, $gid,   $quota,
        $comment, $gcos,   $dir, $shell, $expire
    ) = getpwnam($member);

    #print $name   . "\t"; #DEBUG
    #print length($member) . "\t"; #DEBUG
    #my @pwline = getpwnam($member); #DEBUG
    #print $pwline[0] .  "\n"; #DEBUG

# check if we actually got a pwent structure by checking the UID
#if (!defined($uid)) {
# fail
#	print STDERR "/etc/passwd out of sync with /etc/group - group $groupname member $member not found in /etc/passwd\n";
#	next;
#}

    # build the phonebook table entry
    my %phonebookent =
      map { $_ => "" } @phonebook_keys;    # thanks to raldi@stackoverflow
    @phonebookent{ 'Unix Name', 'E-mail address' } =
      ( $name, "$name\@lakemasoniccenter.org" );

    if ( length($gcos) > 0 ) {
        @gecos = split( /,/, $gcos );
	# 20100531:11 fix a whitespace issue with split(/ / ) that perltidy messed with
        @phonebookent{ 'First Name', 'Last Name' } = split(/ /, $gecos[0] );
        @phonebookent{ 'Office', 'Office Phone', 'Home Phone' } =
          ( $gecos[1], $gecos[2], $gecos[3] );
    }

    else {
        @phonebookent{ 'First Name', 'Last Name' } = ( "", "" );
        @phonebookent{ 'Office', 'Office Phone', 'Home Phone' } =
          ( "", "", "" );
    }

    # housekeeping
    foreach my $key (@phonebook_keys) {

        # 20100531:03 change conditional to a one-liner
        # 20100531:10 reverse direction of conditional
        $phonebookent{$key} = "" unless ( defined( $phonebookent{$key} ) );

        my $columnwidth = length( $phonebookent{$key} ) + 4;

        #DEBUG
        #print $key . "\t" . $columnwidth;

        if ( $columnwidth > $columnwidths{$key} ) {
            $columnwidths{$key} = $columnwidth;

            #print "\nNew Column Width for $key is $columnwidth.\n"; #DEBUG
        }

    }

    # add the entry to the phonebook
    my $phonebookent_ref = \%phonebookent;

    #print "pushing $name\n"; #DEBUG
    push( @phonebook, $phonebookent_ref );
}

# sort the phone book by name (thanks to cbkihong@unix.com, http://www.unix.com/members/20503.html)
@phonebook = sort {
        $$a{'Last Name'}
      . $$a{'First Name'} cmp $$b{'Last Name'}
      . $$b{'First Name'}
} @phonebook;

# print header
my $maxwidth   = 0;
my $numentries = scalar(@phonebook);

#print $numentries; #DEBUG
my $key        = "";
my $entrywidth = 0;
my $padding    = 0;

foreach (@phonebook_keys) {
    $maxwidth += $columnwidths{$_
      };         # add the maximum width of the column to the overall screen max
    print $_;    # print the column header
    $entrywidth = length($_);    # get the actual width of the entry
    $padding =
      $columnwidths{$_} -
      $entrywidth - 2;    # calculate number of spaces needed to pad column

    for ( my $i = 0 ; $i < $padding ; $i++ ) {
        print " ";
    }

}

print "\n";

for ( my $i = 0 ; $i < $maxwidth ; $i++ ) {
    print '-';
}

print "\n";

for ( my $i = 0 ; $i < $numentries ; $i++ ) {
    foreach $key (@phonebook_keys) {
        print $phonebook[$i]{$key};
        $entrywidth = length( $phonebook[$i]{$key} ) + 2;
        $padding    = $columnwidths{$key} - $entrywidth;

        for ( my $j = 0 ; $j < $padding ; $j++ ) {
            print " ";
        }

    }

    print "\n";
}

print "\n";
exit 0;

About these ads