Comprehensive System Administration

Lecture 2 notes:

getting an OCF account:
	Hopefully you've already gotten an OCF account.

	This course will be taught on the Open Computing Facility's hardware.
	If you don't have an OCF account already, you'll need to sign up for one.

	You should have done this on the first day of class.  If you missed it
	you can do it anytime a staff member is around.
	You can go to this page to get the new account form 
	if you'd rather print it and fill it out at home although we usually 
	have copies in the lab.

administrivia:
	Taking this class for units:
	Try to sign up officially before this Friday.  To get a signiture,
	stop by the lab on Thursday afternoon before 6pm, or bring your
	add form to class if you want to wait until the last minute.
	Any class instructor can sign the form, but try to find Gabe or
	Devin.

	We don't mind if you just want to audit the class.

	Class This Friday:
	The lab may be closed this Friday, as Heller Lounge will be 
	closed from Thursday evening until next Tuesday.
	Our staff will try to open the lab, you may need to walk
	around to the back door to get in if the front door is locked.

	In future weeks, we may move the class to a real classroom, 
	because hands on computer use will not always be necessary.

	Units:  variable (1-3)

	Questions?	

course material:

	Today we will focus on getting everyone up to speed on basic unix
	commands, and redirection.  If there is time, you should investigate 
	file editors, and email programs.  You should use the class time to 
	find peers that have more knowledge than you in certain areas, and 
	who you can go to for advice and guidance.

	Steve and Gabe will be leading the class, there will also be other 
	instructors around and available to help.

	Below is a list of basic unix commands we think you should be 
	familiar and comfortable with.  

	These links can help you find information about any commands you 
	don't know already.  You can also try asking your peers, or an 
	instructor.  

	Some hints on getting more information and explanations about unix commands
	
	Google Search for "frequently used unix commands"
	
	LLNL's Quick Reference of Frequently used Unix Commands
		
	Very basic unix commands...





ls

cp, mv, rm
chmod, chown, chgrp

cd, pwd
mkdir, rmdir, ln

cat, more, less, head, tail

man, apropos

sort, uniq, wc, grep

vi, pico, emacs

date, cal

pine, elm, mutt, mail

telnet, rlogin, ssh

ftp, scp

w, who, finger, talk, nwrite

hostname, whoami, set, history

passwd, quota -v, du

lpr, lp

ps, kill

find, locate, which

exit

redirection >, >>, <, |

 >  send output to file:  ls > directory-listing
 >>  append output to end of file (don't overwrite file)
 < send a file as input to a command:   mail friend < filename
 |  send output of one command to input of next command: ls -la | more







Homework
 

Due by next Friday (2/23/2001).  Mail your transcript and any questions to 
jones@xcf.berkeley.edu

1)  Create a transcript that shows you understand several of the commands listed above.
Several people have asked, "what is a transcript?"  By transcript, I mean a file that 
shows the output of your session.  See this example.
Yours will be longer.  You can use the script command to create the transcript, 
or you can cut and paste, whatever works for you.

Don't bother demonstrating knowledge of editors, mail readers, or remote access programs, 
we'll get into more details on those later, if possible, and besides, that will make your
transcript look crufty.
Don't print anything.  
Use flags (options, i.e. "-l" is an option for ls, as in ls -l. 
Do demonstrate the use of input/output redirection.

2) Find another source of interesting or useful information, 
such as the sites and books listed below.  
Google.com's search engine could be useful for this. 
Tell us what the source is, and describe the source briefly.

i.e.

www.sunfreeware.com - it has software packages for various sun operating systems.
or
www.slashdot.org - has news and information about computing and technology

Mail your homework, and any questions to jones@xcf.berkeley.edu

Enrichment

W&MF walk-in courses
A semester in a table from WM&F

CSUA Help Sessions
Help Session Tutorials and Handouts
Online help files from the ME dept

Classes offered by Berkeley's IS&T staff
Help files on Socrates

Computer-Based Training in Management of Information Science (available from UCB hosts only)

If you are interested in running Linux at home, you should visit CalLUG the Cal Linux Users Group.
They have meetings, and links to information about running Linux.

An independent study course from the University of Indiana

A brief description of different Linux distributions

Unix FAQFrequently Asked Questions from the comp.unix.questions newsgroup

Unix Sysadm Resources - another random source

The most used source of information on unix commands is the unix manual pages. E.g. to read the manpage for the ls command, you would type: "man ls". The manual pages are divided up into different sections. Since there are sections for unix commands and sections for the c programming language, and other sections for perl, sometimes the section that the man command will give you by default will not be for the command that you are looking for. E.g. for "less," on some OCF sun boxes, "man less" will return the manpage for a perl pragma (which is found in section 3 of the manpage - the section that is being drawn from is displayed in parentheses in the upper righthand corner along with the commandname (i.e. for less, it looks like "less(3)"), rather than for the unix command. The manpage for the unix command "less" is found the section 1 of the manual, so to get at that manpage, you would need to type "man -s1 less".

Here are some more details about how to read a unix man page.
As a side note, the apropos command is useful for finding which section of the manual the page you are looking for resides. ("apropos less" finds all the manpages which mention the word less in their description.)

E.g. looking for less, we see there are two commands called less, which I've highlighted, one in section (1) and another in section (3).


% apropos less UNIVERSAL UNIVERSAL (3) - base class for ALL classes (blessed references) jpegtran jpegtran (1) - lossless transformation of JPEG files less less (3) - perl pragma to request less of something from the compiler cldap_close cldap_close (3n) - dispose of connectionless LDAP pointer cldap_open cldap_open (3n) - LDAP connectionless communication preparation cldap_search_s cldap_search_s (3n) - connectionless LDAP search cldap_setretryinfo cldap_setretryinfo (3n) - set connectionless LDAP request retransmission parameters min min (9f) - return the lesser of two integers less less (1) - opposite of more lesskey lesskey (1) - specify key bindings for less

Since the manpage for less from section 3 didn't give us what we wanted to see, this suggests we look at the less manpage in the other section ("man -s1 less", even though the description "opposite of more" doesn't really explain anything.

It's also important to know that your shell has built in commands which will probably not have manual pages of their own. For example "man set" on the OCF will find the command "set" for the TCL scripting language, which is probably not what you want. If you type "which set" you will be told that set is a built-in shell command. To read about the set command, you will need to look at the manpage for your shell (e.g. "man csh"). This brings us to the problem of knowing what shell you are using. The most common default shells are sh, csh, bash, and less likely, tcsh or ksh. You can check your processes and find out which shell you are using, e.g. "ps" will give you something like:

% ps PID TTY TIME CMD 10380 pts/4 0:00 tcsh 10362 pts/4 0:00 csh

In this case, the lower numbered PID (process ID) is the shell that the system gave me when I logged in, csh, and tcsh is a shell I ran later and am currently using. To find what the behavior of set would be in my current shell, tcsh, I would look at the tcsh manpage: "man tcsh".

Man pages can be difficult to read, an require some getting used to. You can find information about many commands online. Try a google search for "unix command foo" if the manpage is unhelpful to you.

There are some useful unix books out there. In particular the O'Reilly & Associates "Unix in a Nutshell" is said to have a reasonable level of information about commands, while not being as confusing as a manpage.

My favorite general-purpose book is Unix System Administration Handbook by Nemeth, Snyder, Seebass and Hein. Now in it's third edition, this book provides excellent coverage of many routine system administration tasks. For deeper understanding of a variety of topics, O'Reilly & Associates is my favorite publisher. Their books are nearly always high quality, and are usually written by reputable sources, and occasionally by the actual creators of a tool. For example, the most famous book on Perl is published by O'Reilly and is called Programming Perl was written by Larry Wall, the creator of Perl.

The field of unix system administration really does have it's own culture. Being very computer-centric, there are countless newsgroups, email-lists, irc-channels, and websites dedicated to the task and the surrounding culture. This culture does have it's egos and social-ills, but by and large is very supportive and genial.

The System Administrator's Guild - SAGE, a professional organization for SysAdmins
Slashdot - news of interest to the geek community
User Friendly - a comic about a software company
Cyberspace Atlas - interesting information with a cheesy name