For People New to Both FreeBSD and UNIX®

Annelise Anderson

<andrsn@andrsn.stanford.edu>

Revision: 52136

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Last modified on 2018-08-16 13:55:09 by bcr.

Abstract

Congratulations on installing FreeBSD! This introduction is for people new to both FreeBSD and UNIX®—so it starts with basics.

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1. Logging in and Getting Out

Log in (when you see login:) as a user you created during installation or as root. (Your FreeBSD installation will already have an account for root; who can go anywhere and do anything, including deleting essential files, so be careful!) The symbols % and # in the following stand for the prompt (yours may be different), with % indicating an ordinary user and # indicating root.

To log out (and get a new login: prompt) type

# exit

as often as necessary. Yes, press enter after commands, and remember that UNIX® is case-sensitive—exit, not EXIT.

To shut down the machine type

# /sbin/shutdown -h now

Or to reboot type

# /sbin/shutdown -r now

or

# /sbin/reboot

You can also reboot with Ctrl+Alt+Delete. Give it a little time to do its work. This is equivalent to /sbin/reboot in recent releases of FreeBSD and is much, much better than hitting the reset button. You do not want to have to reinstall this thing, do you?

2. Adding a User with Root Privileges

If you did not create any users when you installed the system and are thus logged in as root, you should probably create a user now with

# adduser

The first time you use adduser, it might ask for some defaults to save. You might want to make the default shell csh(1) instead of sh(1), if it suggests sh as the default. Otherwise just press enter to accept each default. These defaults are saved in /etc/adduser.conf, an editable file.

Suppose you create a user jack with full name Jack Benimble. Give jack a password if security (even kids around who might pound on the keyboard) is an issue. When it asks you if you want to invite jack into other groups, type wheel

Login group is ``jack''. Invite jack into other groups: wheel

This will make it possible to log in as jack and use the su(1) command to become root. Then you will not get scolded any more for logging in as root.

You can quit adduser any time by typing Ctrl+C, and at the end you will have a chance to approve your new user or simply type n for no. You might want to create a second new user so that when you edit jack's login files, you will have a hot spare in case something goes wrong.

Once you have done this, use exit to get back to a login prompt and log in as jack. In general, it is a good idea to do as much work as possible as an ordinary user who does not have the power—and risk—of root.

If you already created a user and you want the user to be able to su to root, you can log in as root and edit the file /etc/group, adding jack to the first line (the group wheel). But first you need to practice vi(1), the text editor—or use the simpler text editor, ee(1), installed on recent versions of FreeBSD.

To delete a user, use rmuser.

3. Looking Around

Logged in as an ordinary user, look around and try out some commands that will access the sources of help and information within FreeBSD.

Here are some commands and what they do:

id

Tells you who you are!

pwd

Shows you where you are—the current working directory.

ls

Lists the files in the current directory.

ls -F

Lists the files in the current directory with a * after executables, a / after directories, and an @ after symbolic links.

ls -l

Lists the files in long format—size, date, permissions.

ls -a

Lists hidden “dot” files with the others. If you are root, the “dot” files show up without the -a switch.

cd

Changes directories. cd .. backs up one level; note the space after cd. cd /usr/local goes there. cd ~ goes to the home directory of the person logged in—e.g., /usr/home/jack. Try cd /cdrom, and then ls, to find out if your CDROM is mounted and working.

less filename

Lets you look at a file (named filename) without changing it. Try less /etc/fstab. Type q to quit.

cat filename

Displays filename on screen. If it is too long and you can see only the end of it, press ScrollLock and use the up-arrow to move backward; you can use ScrollLock with manual pages too. Press ScrollLock again to quit scrolling. You might want to try cat on some of the dot files in your home directory—cat .cshrc, cat .login, cat .profile.

You will notice aliases in .cshrc for some of the ls commands (they are very convenient). You can create other aliases by editing .cshrc. You can make these aliases available to all users on the system by putting them in the system-wide csh configuration file, /etc/csh.cshrc.

4. Getting Help and Information

Here are some useful sources of help. Text stands for something of your choice that you type in—usually a command or filename.

apropos text

Everything containing string text in the whatis database.

man text

The manual page for text. The major source of documentation for UNIX® systems. man ls will tell you all the ways to use ls. Press Enter to move through text, Ctrl+B to go back a page, Ctrl+F to go forward, q or Ctrl+C to quit.

which text

Tells you where in the user's path the command text is found.

locate text

All the paths where the string text is found.

whatis text

Tells you what the command text does and its manual page. Typing whatis * will tell you about all the binaries in the current directory.

whereis text

Finds the file text, giving its full path.

You might want to try using whatis on some common useful commands like cat, more, grep, mv, find, tar, chmod, chown, date, and script. more lets you read a page at a time as it does in DOS, e.g., ls -l | more or more filename. The * works as a wildcard—e.g., ls w* will show you files beginning with w.

Are some of these not working very well? Both locate(1) and whatis(1) depend on a database that is rebuilt weekly. If your machine is not going to be left on over the weekend (and running FreeBSD), you might want to run the commands for daily, weekly, and monthly maintenance now and then. Run them as root and, for now, give each one time to finish before you start the next one.

# periodic daily
output omitted
# periodic weekly
output omitted
# periodic monthly
output omitted

If you get tired of waiting, press Alt+F2 to get another virtual console, and log in again. After all, it is a multi-user, multi-tasking system. Nevertheless these commands will probably flash messages on your screen while they are running; you can type clear at the prompt to clear the screen. Once they have run, you might want to look at /var/mail/root and /var/log/messages.

Running such commands is part of system administration—and as a single user of a UNIX® system, you are your own system administrator. Virtually everything you need to be root to do is system administration. Such responsibilities are not covered very well even in those big fat books on UNIX®, which seem to devote a lot of space to pulling down menus in windows managers. You might want to get one of the two leading books on systems administration, either Evi Nemeth et.al.'s UNIX System Administration Handbook (Prentice-Hall, 1995, ISBN 0-13-15051-7)—the second edition with the red cover; or Æleen Frisch's Essential System Administration (O'Reilly & Associates, 2002, ISBN 0-596-00343-9). I used Nemeth.

5. Editing Text

To configure your system, you need to edit text files. Most of them will be in the /etc directory; and you will need to su to root to be able to change them. You can use the easy ee, but in the long run the text editor vi is worth learning. There is an excellent tutorial on vi in /usr/src/contrib/nvi/docs/tutorial, if you have the system sources installed.

Before you edit a file, you should probably back it up. Suppose you want to edit /etc/rc.conf. You could just use cd /etc to get to the /etc directory and do:

# cp rc.conf rc.conf.orig

This would copy rc.conf to rc.conf.orig, and you could later copy rc.conf.orig to rc.conf to recover the original. But even better would be moving (renaming) and then copying back:

# mv rc.conf rc.conf.orig
# cp rc.conf.orig rc.conf

because mv preserves the original date and owner of the file. You can now edit rc.conf. If you want the original back, you would then mv rc.conf rc.conf.myedit (assuming you want to preserve your edited version) and then

# mv rc.conf.orig rc.conf

to put things back the way they were.

To edit a file, type

# vi filename

Move through the text with the arrow keys. Esc (the escape key) puts vi in command mode. Here are some commands:

x

delete letter the cursor is on

dd

delete the entire line (even if it wraps on the screen)

i

insert text at the cursor

a

insert text after the cursor

Once you type i or a, you can enter text. Esc puts you back in command mode where you can type

:w

to write your changes to disk and continue editing

:wq

to write and quit

:q!

to quit without saving changes

/text

to move the cursor to text; /Enter (the enter key) to find the next instance of text.

G

to go to the end of the file

nG

to go to line n in the file, where n is a number

Ctrl+L

to redraw the screen

Ctrl+b and Ctrl+f

go back and forward a screen, as they do with more and view.

Practice with vi in your home directory by creating a new file with vi filename and adding and deleting text, saving the file, and calling it up again. vi delivers some surprises because it is really quite complex, and sometimes you will inadvertently issue a command that will do something you do not expect. (Some people actually like vi—it is more powerful than DOS EDIT—find out about :r.) Use Esc one or more times to be sure you are in command mode and proceed from there when it gives you trouble, save often with :w, and use :q! to get out and start over (from your last :w) when you need to.

Now you can cd to /etc, su to root, use vi to edit the file /etc/group, and add a user to wheel so the user has root privileges. Just add a comma and the user's login name to the end of the first line in the file, press Esc, and use :wq to write the file to disk and quit. Instantly effective. (You did not put a space after the comma, did you?)

6. Other Useful Commands

df

shows file space and mounted systems.

ps aux

shows processes running. ps ax is a narrower form.

rm filename

remove filename.

rm -R dir

removes a directory dir and all subdirectories—careful!

ls -R

lists files in the current directory and all subdirectories; I used a variant, ls -AFR > where.txt, to get a list of all the files in / and (separately) /usr before I found better ways to find files.

passwd

to change user's password (or root's password)

man hier

manual page on the UNIX® filesystem

Use find to locate filename in /usr or any of its subdirectories with

% find /usr -name "filename"

You can use * as a wildcard in "filename" (which should be in quotes). If you tell find to search in / instead of /usr it will look for the file(s) on all mounted filesystems, including the CDROM and the DOS partition.

An excellent book that explains UNIX® commands and utilities is Abrahams & Larson, Unix for the Impatient (2nd ed., Addison-Wesley, 1996). There is also a lot of UNIX® information on the Internet.

7. Next Steps

You should now have the tools you need to get around and edit files, so you can get everything up and running. There is a great deal of information in the FreeBSD handbook (which is probably on your hard drive) and FreeBSD's web site. A wide variety of packages and ports are on the CDROM as well as the web site. The handbook tells you more about how to use them (get the package if it exists, with pkg add packagename, where packagename is the filename of the package). The CDROM has lists of the packages and ports with brief descriptions in cdrom/packages/index, cdrom/packages/index.txt, and cdrom/ports/index, with fuller descriptions in /cdrom/ports/*/*/pkg/DESCR, where the *s represent subdirectories of kinds of programs and program names respectively.

If you find the handbook too sophisticated (what with lndir and all) on installing ports from the CDROM, here is what usually works:

Find the port you want, say kermit. There will be a directory for it on the CDROM. Copy the subdirectory to /usr/local (a good place for software you add that should be available to all users) with:

# cp -R /cdrom/ports/comm/kermit /usr/local

This should result in a /usr/local/kermit subdirectory that has all the files that the kermit subdirectory on the CDROM has.

Next, create the directory /usr/ports/distfiles if it does not already exist using mkdir. Now check /cdrom/ports/distfiles for a file with a name that indicates it is the port you want. Copy that file to /usr/ports/distfiles; in recent versions you can skip this step, as FreeBSD will do it for you. In the case of kermit, there is no distfile.

Then cd to the subdirectory of /usr/local/kermit that has the file Makefile. Type

# make all install

During this process the port will FTP to get any compressed files it needs that it did not find on the CDROM or in /usr/ports/distfiles. If you do not have your network running yet and there was no file for the port in /cdrom/ports/distfiles, you will have to get the distfile using another machine and copy it to /usr/ports/distfiles. Read Makefile (with cat or more or view) to find out where to go (the master distribution site) to get the file and what its name is. (Use binary file transfers!) Then go back to /usr/local/kermit, find the directory with Makefile, and type make all install.

8. Your Working Environment

Your shell is the most important part of your working environment. The shell is what interprets the commands you type on the command line, and thus communicates with the rest of the operating system. You can also write shell scripts a series of commands to be run without intervention.

Two shells come installed with FreeBSD: csh and sh. csh is good for command-line work, but scripts should be written with sh (or bash). You can find out what shell you have by typing echo $SHELL.

The csh shell is okay, but tcsh does everything csh does and more. It allows you to recall commands with the arrow keys and edit them. It has tab-key completion of filenames (csh uses Esc), and it lets you switch to the directory you were last in with cd -. It is also much easier to alter your prompt with tcsh. It makes life a lot easier.

Here are the three steps for installing a new shell:

Install the shell as a port or a package, just as you would any other port or package.

Use chsh to change your shell to tcsh permanently, or type tcsh at the prompt to change your shell without logging in again.

Note:

It can be dangerous to change root's shell to something other than sh or csh on early versions of FreeBSD and many other versions of UNIX®; you may not have a working shell when the system puts you into single user mode. The solution is to use su -m to become root, which will give you the tcsh as root, because the shell is part of the environment. You can make this permanent by adding it to your .tcshrc as an alias with:

alias su su -m

When tcsh starts up, it will read the /etc/csh.cshrc and /etc/csh.login files, as does csh. It will also read .login in your home directory and .cshrc as well, unless you provide a .tcshrc. This you can do by simply copying .cshrc to .tcshrc.

Now that you have installed tcsh, you can adjust your prompt. You can find the details in the manual page for tcsh, but here is a line to put in your .tcshrc that will tell you how many commands you have typed, what time it is, and what directory you are in. It also produces a > if you are an ordinary user and a # if you are root, but tsch will do that in any case:

set prompt = "%h %t %~ %# "

This should go in the same place as the existing set prompt line if there is one, or under "if($?prompt) then" if not. Comment out the old line; you can always switch back to it if you prefer it. Do not forget the spaces and quotes. You can get the .tcshrc reread by typing source .tcshrc.

You can get a listing of other environmental variables that have been set by typing env at the prompt. The result will show you your default editor, pager, and terminal type, among possibly many others. A useful command if you log in from a remote location and cannot run a program because the terminal is not capable is setenv TERM vt100.

9. Other

As root, you can unmount the CDROM with /sbin/umount /cdrom, take it out of the drive, insert another one, and mount it with /sbin/mount_cd9660 /dev/cd0a /cdrom assuming cd0a is the device name for your CDROM drive. The most recent versions of FreeBSD let you mount the CDROM with just /sbin/mount /cdrom.

Using the live filesystem—the second of FreeBSD's CDROM disks—is useful if you have got limited space. What is on the live filesystem varies from release to release. You might try playing games from the CDROM. This involves using lndir, which gets installed with the X Window System, to tell the program(s) where to find the necessary files, because they are in /cdrom instead of in /usr and its subdirectories, which is where they are expected to be. Read man lndir.

10. Comments Welcome

If you use this guide I would be interested in knowing where it was unclear and what was left out that you think should be included, and if it was helpful. My thanks to Eugene W. Stark, professor of computer science at SUNY-Stony Brook, and John Fieber for helpful comments.

Annelise Anderson, <andrsn@andrsn.stanford.edu>