help - help for new users and administrators
This document is meant to familiarize new users and system
administrators
with OpenBSD and, if necessary, UNIX in general.
Firstly, a wealth of information is contained within the
system manual
pages. In UNIX, the man(1) command is used to view them.
Type man man
for instructions on how to use it properly. Pay especially
close attention
to the -k option.
Other OpenBSD references include the FAQ (Frequently Asked
Questions) located
at http://www.openbsd.org/faq, which is mostly intended for administrators
and assumes the reader possesses a working knowledge of UNIX.
There are also mailing lists in place where questions are
fielded by
OpenBSD developers and other users; see
http://www.openbsd.org/mail.html.
System administrators should have already read the afterboot(8) man page
which explains a variety of tasks that are typically performed after the
first system boot. When configuring any aspect of the system, first consider
any possible security implications your changes may
have.
The Unix shell [Toc] [Back]
After logging in, some system messages are typically displayed, and then
the user is able to enter commands to be processed by the
shell program.
The shell is a command-line interpreter that reads user input (normally
from a terminal) and executes commands. There are many different shells
available; OpenBSD ships with csh(1), ksh(1), and sh(1).
Each user's
shell is indicated by the last field of their corresponding
entry in the
system password file (/etc/passwd).
Basic Unix commands [Toc] [Back]
man Interface to the system manual pages. For any of
the commands
listed below, type man <command> for detailed information on what
it does and how to use it.
pwd Print working directory. Files are organized in a
hierarchy (see
hier(7)) called a tree. This command will indicate
in which directory
you are currently located.
cd Change working directory. Use this command to navigate throughout
the file hierarchy. For example, type cd / to
change the
working directory to the root.
ls List directory contents. Type ls -l for a detailed
listing.
cat Although it has many more uses, cat filename will
print the contents
of a plain-text file to the screen.
mkdir Make a directory. For example, mkdir foobar.
rmdir Remove a directory.
rm Remove files. Files are generally only removable by
their owners.
See the chmod(1) command for information on
file permissions.
chmod Change file modes, including permissions. It is not
immediately
obvious how to use this command; please read its
manual page
carefully, as proper file permissions, especially on
system
files, are vital in maintaining security and integrity.
cp Copy files.
mv Move and rename files.
ps List active processes. Most UNIX-based operating
systems, including
OpenBSD, are multitasking, meaning many programs share
system resources at the same time. A common usage
is ps -auxw,
which will display information about all active processes.
kill Kill processes. Used mostly for terminating runaway/unresponsive
programs, but also used to signal programs for
requesting
certain operations (i.e., re-read their configuration).
date Print the current system date and time.
mail Access mailbox.
logout Log out of the system.
When a command is entered, it is first checked to see if it
is built-in
to the shell. If not, the shell looks for the command in
any directories
contained within the PATH environment variable (see environ(7)). If the
command is not found, an error message is printed. Otherwise, the shell
runs the command, passing it any arguments specified on the
command line.
man(1), whatis(1), whereis(1), afterboot(8)
This manual page was written by Aaron Campbell <[email protected]> and
first appeared in OpenBSD 2.6.
OpenBSD 3.6 October 17, 1999
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