Datasheet
Using help Messages
The -h or --help options are often used to display help messages for a command. The
following example illustrates how to display help for the ogg123 command:
$ ogg123 --help | less
ogg123 from vorbis-tools 1.1.1
by the Xiph.org Foundation (http://www.xiph.org/)
Usage: ogg123 [<options>] <input file> ...
-h, --help this help
-V, --version display Ogg123 version
-d, --device=d uses ‘d’ as an output device
Possible devices are (‘*’=live, ‘@’=file):
oss* null* wav@ raw@ au@
-f, --file=filename Set the output filename for a previously
specified file device (with -d).
...
The preceding output shows how the ogg123 command line is used and lists available
options. Piping the output to the
less command lets you page through it.
Using man Pages
Suppose you want to find man pages for commands related to a certain word. Use the apropos
command to search the man page database. This shows man pages that have crontab
in the man page NAME line:
$ apropos crontab
crontab(1) - maintain crontab files for individual users (V3)
crontab(5) - tables for driving cron
The apropos output here shows each man page NAME line that contains crontab. The
number shows the man page section in which the man page appears. (We discuss sec-
tions shortly.)
The
whatis command is a way to show NAME lines alone for commands that contain
the word you enter:
$ whatis cat
cat (1) - concatenate files and print on the standard output
The easiest way to display the man page for a term is with the man command and the com-
mand name. For example:
$ man find
FIND(1) FreeBSD General Commands Manual FIND(1)
NAME
find -- walk a file hierarchy
9
Chapter 1: Starting with BSD Systems
76034c01.qxd:Toolbox 3/29/08 10:40 AM Page 9