Date: Thu, 17 Sep 1998 08:41:52 -0400 (EDT)
From: chang@UUNET (Michael Chang)
To: swgibson@UUNET (Stephen Gibson)

    The following is a list that corresponds pretty closely with
man pages that need to be read. Don't consider it complete. Also, don't
overestimate what you know already. If you know that tail prints out
the last lines of a file, do you know what tail -f does? Have you
ever actually bothered to read the man page for ls? Even if you've
hacked around with Unix machines before, you might have never booted
one over a network, or built a kernel, or written code to get two
machines talking over the network (or maybe you have…) Even if you
know everything about Unix (you often go bowling with Dennis Ritchie
and drink beer with Ken Thompson), our setup isn't that vanilla so
there's still a lot of localism to learn.
    Also, don't worry if you don't know any of this. You will be
expected to learn how to do a few simple tasks almost immediately,
but after that you will have a while before you get the root passwords
and are expected to know how to use them. By that time we will have
taught you a little and you will have taught yourself a lot of what
you need to know. No one will stand over you with a whip, but if you
put forth some effort then you could come out of this job knowing
a hell of a lot.

    Okay, enough rambling. This is separated into categories that vaguely
correspond to priorities. Dumping is your first priority. Some of these
are things that you need to find out, and some are tips that are just easier
to tell you.

Dumping:

	- what is a filesystem?
	- what is ifs? What does 'df' do? What does 'file server' mean in
	our cad setup?
	- what are the options to dump? On a biweekly we do :
		dump Ousdf 32000 6250 /dev/rts8 /
	What does each of these mean? Tip: never memorize anything.
	- if you have a dump file, how can you get the table of contents?
	- what does shutdown, sync, amount, mount, fsck do?
	- what's the difference between reboot and fastboot?
	- what are the files /etc/motd, for?
	- when you see an executable, your first thought should be "Is this
	a binary or a shell script?" Use the 'file' command.
	- when a BSD machine is booted it runs the shell scripts /etc/rc,
	/etc/rc.local, and on some machines there is a /etc/rc.boot. What
	do these scripts do? What is a daemon?
	- for solaris 2.x machines, they use /etc/rc*.d and /etc/init.d
	startup scripts instead of /etc/rc and /etc/rc.local

Miscellaneous Unix:

	- learn an editor. Type ls -alg 'cfin view vi ex'. These programs are
	all the same, they look at how they were invoked and behave
	accordingly. It's a good idea to learn both vi and emacs. I use
	emacs for general editing but use vi for editing system files as root.
	I also use 'ed' for quick editing of files on the consoles in the
	machine room or on the machines where /usr is not currently mounted.
	- what is the difference between the following:
		mv file1 file2
		   and
		cp file1 file2
		rm file1
	- 'cfin' will give you every occurrence of an executable on your path.
	- what does a .cshrc file do? When you log in, which gets read first,
	your .cshrc or your .login? Why do these files all start with a dot?
	- what dies a .rhosts file do?
	- what is a getty? What does the login program do?
	- what is a link? What's the difference between a hard link and a
	soft link? cd to /usr/spool on one of the workstation, then type
	'pwd'. Why did this happen? Why is this necessary?
	- type 'ls -l'. What does all of this information mean? How do you
	use chmod (do you know octal?) The leftmost letter in the permissions
	is the file type, what is the difference between -,c,b,s,d,l, and the
	ones that I can't think of right now?
	- what does ps do? sys tat (you won't find this everywhere)? vmstat?
	iostat? netstat? the stats that I can't think of?
	- what's the difference between globbing and regular expressions?
	Which programs use which?
	- what does ruptime, ru, rwho do?
	- Do you have a real putty mouth? What does 'wheee, wheee, wheee'
	mean?
	- what does finger do? what is .plan, .project? How about
	finger @amanda?
	- what is news? What does 'rn' do? 'newsgroups'? What is your .newsrc?
	- learn awk. Once you know a little of this, uses for it seem to
	pop up almost every day (well alright, maybe once a week). Read the
	man page and look at the tutorial in one of the Berkeley books (the
	little books with the blue, white, red, or green binders and the
	little daemon on the front) or at the section in Kernighan & Pike.
	- learn how to use 'tar'. You should be able to make a tar file,
	extract one, and get a table of contents from one. What does this
	do:
	rsh amanda 'cd dir2; tar cf - .' |tar xvpf -
	- how come 'ls -lR *.c' doesn't recursively list files that end in .c?
	- how do you recursively list the files that end in .c? (how does
	'find' work)?
	- learn how to use rsh, rcp.
	- read the man pages for 'hier' and 'filesystem' (these aren't
	commands, just man pages.)
	- what is a daemon? what does rwhod, fingerd, mdqsdaemon,
	named, rlogind do? whats special about inetd?

Mail:
	- what does a .forward file do? What's in /var/spool/mail? What's
	in /var/spool/mqueue? What's /etc/aliases.
	- most staff worlders use mh. What does scan, inc, comp, forw,
	repl, rmm, next, prev, folder, refile, show, and pick do? How do you
	specify the editor to use for composing mail? What should be in your
	.mh_profile?
	- what does 'newaliases' do?
	- what does 'biff' do? how does it work? what's the comsat daemon?

Programming and general software stuff:

	- learn c.
	- We have one source machine for each architecture (meaning this is
	the machine on which we keep the source code and do builds.)
	For the workstations, the source machine is the cad AVWI file server
	for that architecture (schwing for SunOS 4.1.3 sparcs, rasheeda
	for decs, ballast for sun3s, uranus for Solaris 2 sparcs).

	- We use rcs here. This is a Revision Control System that does things
	like prevent two people from editing the same source file at the same
	time, it keeps a history of every change you make in a file and allows
	you to retrieve an old version, and generally reduces the potential
	for chaos. Look at the man pages for rcs, co, ci, rcsdiff, rlog.
	Create a file, check it in, check it out, change it and do
	wacky things like that to get a feel for how it works.
	- what does fork do?
	- type man -k socket, what do these do?
	- whats the difference between a unix domain socket and an internet
	domain socket? Write two programs that can talk across the network.
	- what is a signal?
	- what is a pipe? Write a small program that spawns a child and communicates
	with it.
	- write a program that writes and reads a file. What's the difference
	between fopen and open?
	- what does rdist do? Make an rdist file to rdist your .cshrc
	and .login, for instance.
	- learn how makefiles work. Start making makefiles for the programs
	you write for practice. The general procedure for 'make'ing software
	goes something like this:

	make clean	Cleans up the directory by deleting any old .o files
			and executables and core dumps and etc.
	make depend	Looks at all the files and determines the
			interdependencies.
	make		Does the actual compiling.
	make install	Put's the resulting executable into the right
			directory with the right permissions, and installs
			the man page, etc.
	We have two versions of make here: make and pmake. Make is the
	standard unix make and is the one you should concentrate on. Look
	at any makefile that isn't under /usr/src/local. Pmake is a nifty
	Berkeley version of make that depends on using a bunch of include
	makefiles to allow for your makefiles to be tiny. Look at the
	makefiles under /fs/share/src/local. The make include files are in
	/usr/share/mk. If you see .include <local.prog.mk> that means
	include the file from /usr/share/mk.  Pmake is cool, but learn
	regular 'make' first.

Shell stuff:

	- what is a shell? how does the system know which shell to start up
	when you log in? How do you change your default shell?
	- create an alias that uses command-line arguments.
	- read the man pages for sh (the Bourne shell) and csh (the C shell).
	Learn how to use 'if the else' and while and for loops and command
	line arguments and variables and whatever else comes to mind in shell
	scripts and on the command line.
	- what does it mean when the first line of a shell script is this:
		#!/bin/csh
	- what's the difference between 'this' and `this`.
	- how do you trap a control-c in a shell-script (for instance if you
	want to cleanup some temp files before quitting.)
	- can you do file completion in csh?
	- learn how to use csh's history mechanism. What does !-2 do?
	- what are environment variables, like $HOME and $EDITOR? How do you
	access these from a c program? Write one that does it. Learn how to
	set them from both sh and csh. Can you change these from a c program?
	How about a shellscript?

Windowing:

	- how can you run an X command on one machine and have the window
	pop up on another? What does xhost do? What does xallow do?
	What is a MAGIC-COOKIE?
	- what does the 'secure keyboard' thing do? Why is it our friend?

Random system stuff:

	- what are /etc/fstab, /etc/exports for?
	- what does exports do (on SunOs4.1 machines like the upgraded
	sun3's and the sparcstations.)
	- how do you create a mail alias?
	- how do you add someone to a group?
	- what is cron? You can experiment with cron by taking advantage
	of the fact that SunOs4.1 allows each user to create his own
	crontab file. Where is the system crontab file and what kind
	of things do we run every night?
	- what does 'su' do? what does 'user' do?
	- what does it mean for a program to be setuid or setgid?
	How come you can run 'chfinger' which, in effect, edits the password
	file but you can't just edit the password file with vi?

Account stuff:
	- learn the format for the passed file
	- what does /etc/group do?
	- We have quotas on a few machines like tove and the junkfood
	machines. Find out how to check and edit someone's quota.

Good books:
	(in my opinion.) You can find a copy of most of these laying around
	the office. owned by other staffers.
	'The C Programming Language', Kernighan & Ritchie
	'C, A Reference Manual', Harbison & Steele
	'The Unix Programming Environment', Kernighan & Pike
	'A User Guide to the Unix System', Thomas & Yates
	'The Design and Implementation of the 4.3BSD Unix Operating System',
		Leffler, McKusick, Karels, & Quarterman
	'Computer Architecture, a Quantative Approach', Hennessy & Patterson
	'Internetworking with TCP/IP' Comer & Stevens
	'Unix Network Programming' Stevens
	'Advanced Programming in the Unix Environment' Stevens
	'Programming Perl' Wall & Schwartz

	I'm open to suggestions for others.