newbie: misc commands - id, groups, uptime, uname, date, cal, whoami
date: 08.4.99

Misc. commands, lesson one.

The following utilties provide basic information about the system
or other day to day functions. For the most part, they are simple
to use, allow few arguments, and only report a specific bit of
information back.


command: id

This shows your User ID (UID) and Group ID (GID) [as set in /etc/passwd],
as well as all of the groups you are in [set in /etc/groups]. Unix does
all access based off three categories [covered in 'chmod' lesson];
user, group, other. Your UID and GID dictate exactly what kind of file
and permission access you have around the system.

The other utility that quickly shows the groups you are in
is groups. Knowing which groups you are in helps you figure out
what kind of file or directory access you have beyond your own
files.


forced ~$ id
uid=1000(jericho) gid=17(hide)
groups=10(wheel),100(users),101(compiler),102(locate),105(socket),106(shell)

forced ~$ groups
hide root bin wheel users compiler locate socket shell irc malvu
forced ~$  



command: uptime

Uptime tells you how long the system has been up and running since
the last reboot, how many users are currently logged in, and
the load average of the machine. The load average gives a numeric
representation of how much of the CPU is being utilized.


forced ~$ uptime
 11:48pm  up 7 days, 14:29,  4 users,  load average: 0.11, 0.13, 0.09
forced ~$ 



command: uname

The uname command shows various information about the system
you are on. Included in the uname output is the Operating
System, machine name, OS version, and architecture.

By itself, the uname command will only tell you the
Operating System. It is advised that anytime you run the command,
you do so with the -a argument for full information output.

A Slackware Linux machine:

forced ~$ uname -a
Linux forced 2.0.37 #2 Mon Jul 19 16:47:13 MDT 1999 i586 unknown
forced ~$ 


A modified Linux machine:

forced ~$ uname -a
ATTRITION forced 0.0.1 #23 Fri Oct 30 03:52:30 MST 1998 i586 unknown
forced ~$ 


A Sun Microsystem's SunOS machine:

flatland ~$ uname -a
SunOS flatland 4.1.4 3 sun4m
flatland ~$ 



command: date

Gives you the current system date and time. Be careful, if you are
acessing a system across the nation, pay attention to the time zone ;)


forced ~$ date
Thu Nov 26 23:51:55 MST 1998
forced ~$ 



command: cal

cal is short for 'Calendar' and does exactly that. When run by
itself, it displays the current month's calendar.


forced ~$ cal  
    November 1998
Su Mo Tu We Th Fr Sa 
 1  2  3  4  5  6  7
 8  9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30


Calendar is great for displaying more than the current month. When
given the arguments, it will display month and year as desired.

syntax: cal (mo) (year)


forced ~$ cal 12 1998
    December 1998
Su Mo Tu We Th Fr Sa 
       1  2  3  4  5
 6  7  8  9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31

forced ~$ 



command: whoami

Believe it or not, when bouncing around systems or maintenance
accounts, you might not remember who you are logged in as.
So ask the system 'who am i'!


forced ~$ whoami
jericho
forced ~$ 



jericho@attrition.org
(c) copyright 1998, 1999 Brian Martin