This article originally appeared in the January 2003 issue of the Dæmon News Online Magazine. This is a cleaned-up version of the article with minor style edits and made it HTML5 compliant; else, the content has not been changed.
Author: Æleen Frisch
Publisher: O'Reilly & Associates, Inc.
Web Page: http://www.oreilly.com/catalog/esapr/
Published three years ago, UNIX in a Nutshell is a full reference book aimed at system administrators (or sysadmins) as a book that can be used to reference any of the commands and utilities included in UNIX. Unfortunately, the book was geared at System V and its UNIX derivatives; therefore, it may not be quite as useful for BSD sysadmins nor is it portable enough to carry in one's pocket to reference when working away from a desk or on the road. Recently published, a companion to Essential System Administration, 3rd Edition (reviewed this month) is a quick pocket reference for the command, tools and important topics that can be found in the full book. Since it was done after the release of the full book, the round-up of the covered operating systems has been updated, with the exception of HP/Compaq Tru64 (or Digital) UNIX, to include the latest versions. Below is the list of operating systems covered.
Below is the table of contents for the pocket reference.
Under each section, the author includes an explanation of each command and its options and arguments
(along with the different option and argument variations used across the different systems), file
locations for files related to its topic, configuration file syntax, and checklists for important
topics. For example, starting on page 100: the different options and syntax used in both the BIND
named.conf, and the domain map files.
In addition to configuration file syntax and command arguments, there are some tables scattered throughout the pocket reference that can very, very useful. The one that sysadmins will mostly likely love the most is the CIDR table, on page 100, containing CIDR suffixes (in slash notation), its more common dotted-quad subnet mask, and the maximum number of hosts available in the respective subnet (with the network number and the broadcast address subtracted from the count). On the opposite page is another table that lists commonly used TCP and UDP (which is misspelled as "UPD") ports and its associated service.
Being the first printing and edition, there are some typos that I found while reading through it. The
first one that stood out was the variables listed for enabling or setting the syslog dæmon in
FreeBSD on page 23. The second variable listed is "
syslogd_flag"; instead, it should
syslogd_flags". On page 126, the author listed the kernel build directory for
FreeBSD as "
/usr/src/sys/arch/conf", which is actually the location of
the kernel configuration file location. The kernel build directory (when using the old kernel compile
method) should be "
/usr/src/sys/compile/kernel-name" Also, the reason why
arch is that the author should have made a note for the reader to
replace it with the architecture moniker for which the kernel should be built for (this occurs on both
page 126 and on page 127).
Although the author mentions a downloadable log rotation tool,
logrotate in the "System
Messages and Log Files" section, FreeBSD's
newsyslog utility was not covered.
newsyslog can be used to not only rotate the system log file based on the file's size or on a
routine basis, but it can also be used to rotate Apache log files or other program output file. Under
the "Startup and Shutdown" section, the author lists
/etc/rc.* for FreeBSD's
"Secondary boot scripts/script directories", but does not include
as a startup/shutdown script directory.
Looking past the mistakes (which is mostly forgivable since it is the first printing and edition), the pocket reference is something that many sysadmins - including myself - will find to be very useful in the field. There are times that you need to know which command option does what, but a man page could just have a cryptic explanation for it. One option that could be very appealing for some sysadmin is an eBook version of the pocket reference that can be viewed on a PDA. Unless you have memorized every command and its options and variations across the different UNIX systems, the pocket reference is something I would highly recommend getting.
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