I think there is still a mistake in the example for /etc/sudoers (section user
specifications).

In order for a user to be able to sudo all the executables of a directory, this
directory must be written with a '/' at the end.

The last line of the example becomes thus :

BACKUPOPS ALL , !CHEM = BACKUP , /usr/local/bin/

(perhaps this varies depending on the version of sudo).

The sentence "By default, searches are not case sensitive, but you can use -g to make them so." is incorrect.

I don't know that plod has a default search mode. Also, the "-g" option makes the search case-INsensitive.

The sentence "By default, searches are not case sensitive, but you can use -g to make them so." is incorrect.

I don't know that plod has a default search mode. Also, the "-g" option makes the search case-INsensitive.

Setting up man -k

page shows Solaris command as:

#makewhat /usr/share/man Solaris

Should be

#makewhatis /usr/share/man <-- this works on Solaris 8

The top item is not an RG-11 coax connector, it's an AUI connector, I think ... not
directly related to coax cabling.

Primary group attribute
"prgp"
should be:
"pgrp"

The example for the paragraph states:
"auth required pam_listfile.so onerr=fail sense=deny
file=/etc/ftpusers item=user"

The following paragraph says "This entry says that the file /etc/ftpusers (file
argument) contains a list of usernames (item=user) who should be denied access to
ftp (sense=allow)."

I believe that should say "... who should be denied access to ftp (sense=deny)." As
the paragraph continues to state "If you want to grant access to a list of users, use
the option sense=allow."

@ SOA IN should be @ IN SOA. The Linux DNS HOWTO says so, other books says
so and the error messages on my FreeBSD box say so as well...

For the "syslog mail facility messages", /var/adm/maillog is listed for FreeBSD.

FreeBSD does not have /var/adm, like Solaris or Tru64 Unix... instead, all syslog
messages that fall under mail.info get placed under /var/mail/maillog.

The class is called "non_unknown" while It is spelt "no_unknown" everywhere else.

On Solaris, the option to specify filesystem type for mount is -F (this is the case
for Solaris 8 and 9, at least). In addition, the logical device files for block
devices are located in /dev/dsk. So the example for Solaris should be something
like:
mount -o ro -F hsfs /dev/dsk/c0t2d0s0 /mnt

The Tru64 tape devices are listed as:
/dev/[n]rmt/tapen_dm

However, shouldn't it be something like this for Tru64 v5.x:
/dev/[n]tape/tapen_dm

I don't think this script exits with an '-h' flag, as the 'usage' on p. 900
indicates.

If that behavior is intended, you'd want something like:

elsif ($arg eq 'h') { &usage('') && exit; }