||Oracle Tips by Burleson
Getting Help with Linux
Whenever you need detailed help with command syntax or with
command options the man (manual) command will display all
of the information about the specified command that you will
require. The information will be displayed one screen at a time.
When you want to advance to the next screen, press the space
bar. At the end of the display you can use the Q command to
The man pages will tell you the proper command syntax
Enter the man command followed by the name of the
command that you need help with as in the following example:
W(1) Linux User's Manual W(1)
w - Show who is logged on and what they are doing.
w - [husfV] [user]
w displays information about the users currently on the machine, and
their processes. The header shows, in this order, the current time,
how long the system has been running, how many users are currently
logged on, and the system load averages for the past 1, 5, and 15
The following entries are displayed for each user: login name, the
name, the remote host, login time, idle time, JCPU, PCPU, and the
mand line of their current process.
The JCPU time is the time used by all processes attached to the tty.
It does not include past background jobs, but does include currently
running background jobs.
The PCPU time is the time used by the current process, named in the
-h Don't print the header.
-u Ignores the username while figuring out the current process and
cpu times. To demonstrate this, do a "su" and do a "w" and a "w
-s Use the short format. Don't print the login time, JCPU or PCPU
-f Toggle printing the from (remote hostname) field. The
released is for the from field to not be printed, although your
system administrator or distribution maintainer may have compiled
a version in which the from field is shown by default.
-V Display version information.
user Show information about the specified user only.
information about who is currently logged on
/proc process information
The above book excerpt is from:
Working Examples of Linux Command Syntax