Your instructor may indicate some updates or changes to these exercises. The initial exercises are to finalize our machine configurations for use later today, Tuesday and Wednesday, as well as to highlight some areas that are different from Linux - particularly methods by which you can install software.

During these exercises we reference the machine named "noc". This is the classroom server box. It's fully qualified name for this workshop is noc.pacnog.school.fj, but just "noc" should work as well.

 
Exercises

Final Configuration
1. Use pw to create a new userid that you will use instead of root
2. Use /stand/sysinstall and pkg_add to install lynx, bash, sudo and joe
3. Installing two more packages (gmake, unzip)
4. Installation of software using ports
5. Setup sudo for privileged commands
6. Installing/configuring X11 (Xorg), Gnome and gdm

Some Differences from Linux

7. Process startup and the RC system
8. Disk partitions: how to view your disk
9. Getting help using manpages, docs, and the FreeBSD Handbook
10. Shutdown and reboot your system

For Those who Want More Practice

11. Initial login, virtual terminals, command line manipulation
12. General job control (ctrl-c, ctrl-z, bg)
13. Processes and stopping them
14. Use top to see the state of your system
15. Create a file and use vi to edit the file
16. Using vipw to edit a user entry
17. Practice with basic filesystem commands
18. Command pipes and grep
19. Searching for more information about your system
20. File and directory permissions
21. Commands - programs - shell - path

To be Done Last by Everyone

22. Update your /usr/ports collection using cvsup

Note 2: If you install software, update your environment as root and the change is not immediately available try typing rehash at the root shell prompt. This is only necessary when running a C shell (e.g., like /bin/csh).

1.) Use pw to create a new userid that you will use instead of root [Top]

First login to your computer if you have not already done so. Login as userid "root" using the password given at the start of class and that you used while installing FreeBSD.

Now that you are root you can create a new user account on your machine. If more than one person is using your machine, then be sure that you create an account for each and every person.

To create or remove a user account you should use the "pw" command. To get a feel for the power and complexity of this command take a look at its man pages:

# man pw

# pw useradd username -m -s /usr/local/bin/bash

Next you need to set the password for the new userid, otherwise you won't be able to use the account properly. To do this use the passwd command like this:

# passwd username

• Password should be at least 6 characters in length.
• Don't use any words in a dictionary in any language - forwards or backwards.
• The password should contain a mix of letters, numbers, and upper and lower-case letters.

So, finally, let's change your new user's password using the command:

# passwd username

2.) Use /stand/sysinstall and pkg_add to install lynx, bash, and joe [Top]

For this exercise you need to be logged in as root.

FreeBSD has a large collection of preconfigured binary packages for each release that can be installed in a number of ways, including:

1. Using the post-installation configuration utility /stand/sysinstall (don't use this now).
2. Directly from the FreeBSD installation CD-ROMs using pkg_add.
3. From a local network collection of FreeBSD packages specifying the network path and protocol using pkg_add.
4. Blindly across the network using the "-r" option of the pkg_add command

pkg_add
pkg_delete
pkg_info

# man pkg_delete

# man pkg_add

For our first package we are going to install a text-based web browser called lynx. We'll use the /stand/sysinstall program to install lynx from the first disc of the FreeBSD CD-ROM installation set.

First,you can see if lynx is already installed on your system. Use the pkg_info command to do this. To get an idea of what packages are installed and what the default pkg_info output looks like type:

# pkg_info | more

Now to check for just the lynx package type:

# pkg_info | grep lynx
or
# pkg_info lynx\*

If lynx is already installed, for purposes of this exercise, first remove the package from our system (it's good practice!). You can do this by typing:

# pkg_delete lynx-2.8.5

# pkg_info | grep lynx

Now to install lynx using the FreeBSD install CD-ROM do the following:

Insert the FreeBSD Disc 1 Installation CD in your machine's CD-ROM drive.
Be sure that you are logged in as the root user:

Now start the "sysinstall" utility by typing:

# /stand/sysinstall

At this point you take the following steps in the sysinstall menu system to choose the lynx package and install it:

• Choose "Configure" (you can press "C" and ENTER)
• Arrow down to "Packages" and press ENTER
• For installation media choose "CD/DVD" and press ENTER (note you can use network options here)
• If prompted choose "acd0" for your CD-ROM drive
• Scroll down the list of presented categories (using the down arrow key) until you see "www", and press ENTER
• Scroll down to "lynx-2.8.5" to highlight this then press the spacebar to choose the package, then press ENTER
• Now choose "Install" and press ENTER to install Lynx version 2.8.5 on your system

At this point you will be prompted for disc 2 of the FreeBSD installation set. Most of the FreeBSD packages have been moved to this disc. Go ahead and follow the on-screen instructions to swap cd-roms.

• Once installation is complete you will be presented with the initial FreeBSD Configuration Menu - Scroll to the top of the screen and choose "X" for "Exit" and press ENTER
• Finally choose "Exit Install" to leave the "sysinstall" utility

After exiting this utility your FreeBSD install CD-ROM may still be mounted. You can type "df" and look for an entry like this:

Filesystem  1K-blocks     Used    Avail Capacity  Mounted on
/dev/acd0      660384   660384        0   100%    /cdrom

If you don't see the "/cdrom" entry, then type:

# mount /cdrom

again to make sure your CD-ROM (FreeBSD disc 2) is correctly mounted.

Installation of bash

Now let's install the bash package using a single command. As your FreeBSD CD-ROM is mounted under /cdrom, and as your instructor knows where the bash package resides on your CD, you could install bash by typing:

# pkg_add /cdrom/packages/shells/bash-3.0.16_1.tbz

But, rather than doing this, let's do this a bit differently. First use the cd (Change Directory) command to change to the initial cd-rom directory. Then we'll change to the directory /cdrom/packages/All. The "All" directory contains a list of all packages available to be installed on the cd-rom. It has the advantage that if you use pkg_add installing from this directory that if there are dependent packages that are needed, then they will be found and installed as well. So, first do:

# cd /cdrom

# cd packages/All

Now let's look for the bash package. We can use the ls command to do this with a wildcard. You'll be practicing and learning much more about these basic system commands in a few more exercises. OK, so do:

# ls bash*

You should see bash-3.0.16_1.tbz on your screen. This is how you know the exact name of the package you want to install. In addition, once you have installed and are using the bash package it will be easy to use command completion to figure out complicated filenames like these. You'll see more of this in exercise 7. So, now that you know you want to install the package called bash-3.0.16_1.tbz (we're going to use the newer version vs. the 2.05b version that's listed), and you are already in the directory where this file resides, then you can simply type:

# pkg_add bash-3.0.16_1.tbz

and the bash package will be installed. By the way, bash is an alternate shell environment that you can use which has more features than the default shell sh. Notice the file extension of "tbz" on the file bash-3.0.16_1.tbz, this means that the file is actually a group of files that have been compressed and saved as a single file.

Installation of joe

Some of you may practe the use of the "vi" editor, which is not as friendly as the optional "joe" editor. There are reasons for this, which we'll explain. But, for later exercises let's install "joe" right now, but this time we'll install from our local workshop server. If the server name is different than what is shown below your workshop instructor will let you know.

To install the "joe" editor from the local workshop server you can simply type the following:

# pkg_add ftp://noc/pub/FreeBSD/packages/All/joe-2.8_5.tbz

This will download and install the joe 2.8_5 package to your machine from the local workshop server. Note that this editor has been added by us. It no longer ships with the default FreeBSD installation.

Do a little bit of exploring about what you have just installed by entering the following commands:

# man lynx (we'll discuss man a bit later)

# man bash

# man joe

# pkg_info lynx-2.8.5

# lynx www.freebsd.org

'q' (to 'q'uit lynx)

# joe

ctrl-c (to abort, you can say "no" to saving data)

 

3.) Installing two more packages (gmake, unzip) [Top]

For this exercise you need to be logged in as root.

During the week we will need two additional packages to do our work. The two packages we need are:

• gmake: The GNU Make utility.
• unzip: List, test and extract compressed files in a ZIP archive.

Both of these items are packages available on the first FreeBSD CD-ROM. We have placed these files on our classroom server in the /pub/FreeBSD/packages directory. So, to install these three packages simply issue the following three commands

# pkg_add ftp://noc/pub/FreeBSD/packages/All/gmake-3.80_2.tbz

# pkg_add uftp://noc/pub/FreeBSD/packages/All/unzip-5.52_1.tbz

If you want to learn more about these three packages you can type:

# man gmake

# man unzip

 

4.) Installation of software using ports [Top]

For this exercise you need to logged in as root.

The ports collection, which we installed during the FreeBSD install, is larger than the packages collection available on the first FreeBSD install cd-rom. As of June 2004 there were over 13,000 ports available! The FreeBSD Handbook has an excellent discussion of using Ports in section 4.5. In a nutshell these are the key points to remember about ports:

• The ports collection you installed contains descriptive files about how to make a software package and where to get the actual source files. The actual source files (referred to as "distfiles") are not installed.
• You can tell your machine to find distfiles on a local server, or you can get them from CD-ROM, otherwise when you install a port file the software source will be downloaded from the Internet.
• You can use the cvsup tool to keep your ports collection up-to-date. That is, all the descriptive files of where to find source, version numbers, etc.
• Once you have installed a software package using ports it is possible to "deinstall" the package.
• There is a tool called portupgrade which will find all installed ports and keep them up-to-date.
• If you have a ports distfiles cd-rom it needs to be mounted as /cdrom for the ports utilities to find the distfiles.

The very first thing we are going to do is to update a master configuration file so that when you attempt to install a port it will look on our local server for the distfiles rather than using our single outgoing link to fetch distfiles from the internet.

To do this you should edit the file (use joe or vi) /etc/make.conf and add the following two lines to the end of the file:

MASTER_SITE_BACKUP=ftp://noc.pacnog.school.fj/pub/FreeBSD/ports/distfiles/${DIST_SUBDIR}/
MASTER_SITE_FREEBSD=yes

Remember to replace "noc" with what we gave you at the start of these exercises. Now that this is done we are going to install the following port:

• lsof: LiSt Open Files. Shows information about files opened by processes.

First do the following:

# cd /usr/ports
# make search name=lsof

This will output something like:

Port:   lsof-4.72.2
Path:   /usr/ports/sysutils/lsof
Info:   Lists information about open files (similar to fstat(1))
Maint:  obrien@FreeBSD.org
B-deps:
R-deps:
WWW:    http://people.freebsd.org/~abe/

From this you can see that the lsof utility resides in /usr/ports/sysutils/lsof. So, to install lsof on your system you do the following:

# cd /usr/ports/sysutils/lsof
# make
# make install

Make will download the lsof source (hopefully from our local server!), and then compile the source. "Make install" will place the compiled binary files in the appropriate directories on your system and update the appropriate configuration files if necessary. You can issue the single command "make install" instead.

You can now type:

# man lsof

For more information. Finally, if you want to deinstall a port once it is installed, for instance lsof, you would do the following (please don't do this):

# cd /usr/ports/sysutils/lsof
# make deinstall

And, if you decided that was a mistake, you can now do the following to reinstall a port (after it's been installed once):

# cd /usr/ports/sysutils/lsof
# make reinstall

If you do a "make clean" then "make reinstall" will no longer work for that port. If you want to see lsof in action you can type:

# lsof -i

In addition, FreeBSD installs the utilities fstat, and sockstat that can display the same information.

 

5.) Using sudo for privileged commands [Top]

When you created your own user account username you did not place it in the wheel group. This means that you cannot become the root user from your username using the command su. This is a useful thing to be able to do if you don't want to have to logout and log back in each time you need to be root. In addition, the change we are going to make to the "sudoers" file, which controls access to the sudo command is based on your username being in the wheel group. So, the first thing you need to do is be sure you are logged in as root:

$ exit

Login: root

Now we are going to use the pw command to make a change to your username account make it a member of the wheel group. The wheel group is a special group in Unix that allows members to become root. To do this type:

# pw usermod username -G wheel

The "-G" indicates "group list". If your user already belongs to other groups you must include all these groups in list format (e.g. "group1,group2,group3,etc.), otherwise your user will be removed from the other groups when you issue this command. To see what groups a user belongs to you can type:

# groups username

Once your user is a member of the wheel group you can use the su (Substitute User identity) command to become another user without having to login and logout of your session.

To practice this you need to login as your username account now:

# exit

$ Login: username

Now you can practice using su.

$ su - root

If you skip the "-" option, then you won't execute the root login scripts. In general you can type "su user", or "su - user", and switch to any user's environment.

Now let's drop back to your standard user account and try to do something that requires privileges:

# exit

$ less /etc/master.passwd

You should get the message, "/etc/master.passwd: Permission denied" - Now try running the same command like this:

$ sudo less /etc/master.passwd

You noticed that this did not work, right? First we need to add a package called "sudo" to your machine, then we need to configure the file /etc/sudoers to allow you to use this facility. Let's get the package installed first. We'll use pkg_add and we'll get it from our local server:

$ su - (you must be root to install this package)

# pkg_add ftp://noc/pub/FreeBSD/packages/All/sudo-1.6.8.7.tbz

Now we need to configure the file /etc/sudoers so that you can use the sudo command:

# visudo

This is a special utility to edit the /etc/sudoers file using vi, but to lock the file so that no one else can edit it while you are using visudo. So, remember your vi commands and scroll down the screen until you find the following lines in the file (if you need help with vi ask your instructor or one of the classroom helpers):

## root and users in group wheel can run anything on any machine as any user
#root           ALL = (ALL) ALL
#%wheel         ALL = (ALL) ALL

(Note/hint: there are other ways of finding this line in vi. You could search for something using "/".).

Now, once you are here, just make one, small change. Remove the "#" symbol (it's a comment symbol) from in front of "%wheel". Once you do this save and quit from the file. So, your file should now look like:

## root and users in group wheel can run anything on any machine as any user
#root           ALL = (ALL) ALL
%wheel         ALL = (ALL) ALL

And, to save and quite it's:

:wq

That's it. You are now ready to run "sudo" as a general user (or, at least a general user in the wheel group). Make sure you exit from the root shell you are in:

# exit

And, now as a general user, try issuing the command:

$ sudo less /etc/master.passwd

You will be prompted for a password, and the first time you use sudo you'll receive a warning. The password you should enter will be your user account's password. This is different from Linux. Type this in, and you should be able to view the /etc/master.passwd file even though you are running as a standard user. Try doing this again ("less /etc/master.passwd") and you'll notice that you are no longer prompted for the root password. You can issue any privileged command (pretty much) without needing a password at this point. Once you login and logout again, then you'll have to enter a password the next time you use sudo.

sudo is very useful to allow you to do system administration tasks on your machine without needing to be logged in as root. This can help to protect you from making mistakes running as root, which can be costly.

 

6.) Installing/configuring X11 (Xorg), Gnome and gdm [Top]

For this exercise you will need to be logged in as root.

Before we begin there are a few items to understand to put this in perspective:

• A much more complete discussion of using X and Desktops under FreeBSD can be found in Chapter 5, The X Windows System, of the FreeBSD Handbook. I highly recommend reading this entire chapter if you wish to fully configure your X Window environment for FreeBSD.
• FreeBSD is a server-based operating system. Configuration of X, display managers, and desktops like Gnome and KDE are not done during installation as this is not the objective of the OS.
• You can configure FreeBSD to autostart in to a GUI environment, but I would not recommend this, except, possibly, for desktop and laptop use.
• To automate the use of X Window you can edit /etc/ttys (see the Handbook), xinitrc, .xinitrc, .xsession, Xsession, and KDE config files to your liking. For our purposes we are going to install Gnome and manually call the Gnome Dislpay Manager (gdm) when we wish to use an X Window environment.
• X11 is the implementation of the X Windows environment. Xorg is the X11 implementation that FreeBSD uses by default. You can still use XFree86 if you wish, but configuring Xorg is easier. Gnome and KDE are Desktop environments that include Window managers and entire sets of desktop applications.
• You can clean up and make your font environment considerably nicer under X, particularly fonts used by OpenOffice, Netscape/Mozilla/Firefox, and The Gimp. This is easier to do using Xorg. Read Chapter 5 of the FreeBSD Handbook for more details.
• The Gnome and KDE installations that come with the FreeBSD 5.4 CD-ROM installer are quite up-to-date (as of June 2005). The Gnome version is 2.10 and KDE is version 3.4. Gnome version 2.10.1 is available via the ports tree, and you can read about Gnome on FreeBSD here:

  http://www.freebsd.org/gnome/

  You can read about KDE on FreeBSD here:

  http://freebsd.kde.org/

• If you plan on installing both Gnome and KDE and/or possibly offering up Desktop environment via your network from a server, then you will most likely use the KDE Display Manager (kdm) or, possibly the X Display Manager (xdm). kdm can offer access to both Gnome and KDE Desktop environments at loging.

For this workshop we are going to install Gnome from your FreeBSD CD-ROM install set and we are going to use gdm manually to start our X Window environment. We have already configured an Xorg configuration file for your particular machines setting the correct monitor refresh rates and setting your desktops to use 24-bit color at a depth of 1024x768. You will be copying this file from our classroom server, noc, to the appropriate location.

During our initial installation of FreeBSD we installed Xorg, but we have not yet configured it to run on our hardware. First, let's install Gnome using the sysinstall utility.

Start the sysinstall utility (as root) by typing:

# /stand/sysinstall

At this point you take the following steps in the sysinstall menu system to choose the Gnome packages and install them:

• Choose "Configure" (you can press "C" and ENTER)
• Arrow down to "Packages" and press ENTER
• For installation media choose "CD/DVD" and press ENTER (note you can use network options here)
• If prompted choose "acd0" for your CD-ROM drive
• Scroll down the list of presented categories (using the down arrow key) until you see "gnome", and press ENTER
• Scroll down the list to "gnome2-2.10.0" to highlight this then press the spacebar to choose the package, then press ENTER

You should have noticed that multiple Gnome packages are automatically chosen as dependencies (a "D" appears in the selection boxes vs. an "X") when you choose just gnome2-2.10.0.

• Now choose "Install" and press ENTER to install Gnome version 2.10.0 on your system

At this point you will be prompted for disc 2 of the FreeBSD installation set. Most of the FreeBSD packages have been moved to this disc. Go ahead and follow the on-screen instructions to swap cd-roms.

• Once installation is complete you will be presented with the initial FreeBSD Configuration Menu - Scroll to the top of the screen and choose "X" for "Exit" and press ENTER
• Finally choose "Exit Install" to leave the "sysinstall" utility

At this point both Xorg (the X11 X Window system) and Gnome are installed on your system.

Configuration follows.

 

Some Differences from Linux

7.) Process startup and the RC system [Top]

This is a rather complex topic. But, in a nutshell, under FreeBSD 5.4, when your machine boots processes (that is daemons or services) are configured and/or started like this:

• Items that are configured or referenced to start in the file /etc/defaults/rc.conf contain corresponding script entries in /etc/rc.d/.
• You can override settings in /etc/defaults/rc.conf by placing settings in /etc/rc.conf.
• Every script in /etc/rc.d/ will attempt to run, but if it does not see:
  script_enable="YES"
  in /etc/defaults/rc.conf or /etc/rc.conf then the script will not run to start the corresponding service.
• Some third party software will place entries in /etc/rc.conf and corresponding third party startup script packages in /usr/local/etc/rc.d/.
• Some third party packages will place startup/config scripts in /usr/local/etc/rc.d/ that do not look in any file, but simply execute upon system boot.
• Some older software may still place startup items in /etc/rc.local, but this has been deprecated, even though it is still supported.

To get a better feel for this you should read:

$ man rc

Then, you should probably read this again...

Now, if you want to start a process each time your machine boot you generally add an item to /etc/rc.conf to indicate this. For instance, if you wanted to enable the ssh daemon (server) each time your machine started then you would add the line:

sshd_enable="YES"

to /etc/rc.conf. If you look at /etc/defaults/rc.conf you'll see that sshd is not enabled in this file by default. By enabling sshd in /etc/rc.conf this overrides the setting in /etc/defaults/rc.conf. In addition, if you look in /etc/rc.d/ you'll find an sshd script file that starts this service.

To see how sshd is enabled initially do this:

$ grep sshd /etc/defaults/rc.conf

You should see something like:

sshd_enable="NO"                # Enable sshd
sshd_program="/usr/sbin/sshd"   # path to sshd, if you want a different one.
sshd_flags=""                   # Additional flags for sshd.

These are the lines in /etc/defaults/rc.conf that deal with the ssh daemon. When you specified to enable the ssh daemon during installation then in the file /etc/rc.conf the lines that read:

sshd_program="/usr/sbin/sshd"   # path to sshd, if you want a different one.
sshd_flags=""                   # Additional flags for sshd.

became active. So, if your ssh program was not "/usr/sbin/sshd" for some reason, then in /etc/rc.conf you could add:

sshd_program="/new/directory/sshd"   # new path to sshd

to override what's in /etc/defaults/rc.conf.

You could just put everything in /etc/defaults/rc.conf, but you don't want to do this. If you upgrade your system it's almost certain that /etc/defaults/rc.conf could be overwritten. In addition, this file is large and it would be hard to see the changes you had made if you were to do them in /etc/defaults/rc.conf.

To start a service manually you can use it's startup script by hand. For instance, try typing:

$ su - (you must be root to run these commands)

# /etc/rc.d/sshd

What is returned on the screen? It should be something like:

Usage: /etc/rc.d/sshd [fast|force|one](start stop restart rcvar keygen reload status poll)

So, you could type

# /etc/rc.d/sshd status

to see if ssh is running. If it is, then try:

# /etc/rc.d/sshd stop

to start the service. Now type:

# /etc/rc.d/sshd start

to restart the service. Note the startup script option "reload" - This would let you make changes to the ssh configuration file(s) and then reload the service without actually stopping it so that it reads the new configuration. Note that already connected clients would not see this new configuration change until the logoff and log back in again.

Finally, and this is not obvious, if a startup script in /etc/rc.d has not been enabled in /etc/defaults/rc.conf or /etc/rc.conf, then even if you manually invoke the script it will not run. You will not get any indication of this other than the service not starting (i.e. use "ps auxw| grep servicename" and you won't see it started).

At this point take a closer look at /etc/rc.d/

# ls /etc/rc.d

and use "man" to read about some of the services. If you want to try and start and stop some of these services feel free to do so now, but remember you'll need to add 'servicename_enable="YES"' in /etc/rc.conf for the service to start.

 

8.) Disk partitions: how to view your disk [Top]

First, make sure you are logged in as your user and not as root.

Now in a terminal lets look at the partitions. Type:

$ df
$ df -h

What difference did you see between "df" and "df -h". How can you see what your swap contains (note it was not listed using "df")? Use this:

$ swapinfo

If you want to see more detailed information about your disk slices you can use the "fdisk" command. As a general user you are not allowed to run this program, so you must use sudo. Try this by typing:

$ sudo fdisk

Be careful with fdisk as you can remove slices, partitions, etc.

If you are interested in how much space files are taking up in a directory or a group of directories you can use the "du" command. Try it out by typing:

$ du

$ du -h

As usual you can get more information by typing "man du".

Now that you've seen these methods for viewing disk information, you should be able to understand the output of the disklabel command a little better. The disklabel command is really the proper way to view the status of partitions in your FreeBSD slice at it will show you all your FreeBSD slice information no matter if a partition is mounted or not. In some cases this is critical if you are trying to troubleshoot problems and not all partitions have mounted. So, if FreeBSD resides on the slice /dev/ad0s1 on your disk, then to see disk information you can type (as a normal user): $ sudo disklabel /dev/ad0s1

Open: vi fn, vi -r fn, vi + fn, vi +n fn, vi +/pat fn
Close: :w, :w!, :wq, :wq!, :q, :q!
Movement: h,j,k,l, w, W, b, B, :n
Editing: i, o, x, D, dd, yy, p, u
Searching: /pattern, ?pattern, n, N

                        vi Cheat Sheet

Open:  

vi filename             (fn=filename)
vi -r filename          Recover a file from a crashed session
vi + filename           Place the cursor on last line of file.
vi +n filename          Place the cursor on line "n" of file.
vi +/pat filename       Place cursor on first occurrence of "pat"tern

Close:

:w                      Write the file to disk. Don't exit.
:w!                     Write the file to disk even if read/only.
:wq                     Write the file to disk and exit.
:wq!                    Write the file to disk even if read/only and quit.
:q                      Quit the file (only if no changes).
:q!                     Quite the file even if changes.

Movement:

A                       Move to end of line, change to insert mode.
h                       Move 1 space backwards (back/left arrow).
j                       Move down 1 line (down arrow).
k                       Move up 1 line (up arrow).
l                       Move 1 space forwards (forward/right arrow)
w                       Move cursor to start of next word.
W                       Same as "w".
b                       Move cursor to start of previous word.
B                       Same as "b".
:n                      Go to line number "n" in the file.

Editing:

i                       Enter in to input mode.
o                       Add a line below cursor and enter in to input mode.
x                       Delete character (del key in some cases).
D                       Delete line from right of cursor to end of line.
dd                      Delete entire line.
u                       Undo last edit or restore current line.
p                       Put yanked text before the cursor.
yy                      Yank current line.

Searching:

/pattern               Search for "pattern" in the file going forwards.
?pattern               Search for "pattern" in the file going backwards.
n                      Find the next occurrence of pattern found forwards.
N                      Find next occurrence of patter found backwards.

Copy/Cut and Paste
nyyp                   Copy n lines to buffer, paste below cursor
nyyP                   Copy n lines to buffer, paste above cursor
nddp                   Cut n lines and copy to buffer, paste below cursor
nddP                   Cut n lines and copy to buffer, paste above cursor

username:#1#swefo/qx#IUYRRAD09DAAD.:1001:0::0:0:User &:/home/username:/usr/local/bin/bash

username:#1#swefo/qx#IUYRRAD09DAAD.:1001:0::0:0:New User:/home/username:/usr/local/bin/bash

username:#1#swefo/qx#IUYRRAD09DAAD.:1001:0::0:0:New User:/home/username:/bin/sh

pop3pw          106/tcp    3com-tsmux   #Eudora compatible PW changer
pop2            109/tcp    postoffice   #Post Office Protocol - Version 2
pop2            109/udp    postoffice   #Post Office Protocol - Version 2
pop3            110/tcp    #Post Office Protocol - Version 3
pop3            110/udp    #Post Office Protocol - Version 3
hybrid-pop      473/tcp
hybrid-pop      473/udp
pop3s           995/tcp    spop3        # pop3 protocol over TLS/SSL
pop3s           995/udp    spop3
kpop            1109/tcp   #Unofficial
kpop            1109/udp   #Unofficial

drwxrwxr-x    3 hervey   hervey       4096 Feb 25 09:49 directory
-rwxr--r--   12 hervey   hervey       4096 Feb 16 05:02 file

Type User    Group World Links  owner  group  size   date   hour  name
d    rwx     rwx   r-x   3      hervey hervey 4096   Feb 25 09:49 directory
-    rwx     r     r     12     hervey hervey 4096   Feb 16 05:02 file

Letter  Permission   Value

R       read         4
W       write        2
X       execute      1

Letter  Permission                   Value

---     none                         0
r--     read only                    4
rw-     read and write               6
rwx     read, write, and execute     7
r-x     read and execute             5
--x     Execute                      1

Permissions  Numeric      Description
             equivalent  

-rw-------   600          Owner has read & execute permission.
-rw-r--r--   644          Owner has read & execute.
                          Group and world has read permission.
-rw-rw-rw-   666          Everyone (owner, group, world) has read & write
                          permission (dangerous?)
-rwx------   700          Onwer has read, write, & execute permission.
-rwxr-xr-x   755          Owner has read, write, & execute permission.
                          Rest of the world has read & execute permission
                          (typical for web pages or 644).
-rwxrwxrwx   777          Everyone has full access (read, write, execute).
-rwx--x--x   711          Owner has read, write, execute permission.
                          Group and world have execute permission.
drwx------   700          Owner only has access to this directory.
                          Directories require execute permission to access.
drwxr-xr-x   755          Owner has full access to directory. Everyone else
                          can see the directory.
drwx--x--x   711          Everyone can list files in the directory, but group
                          and world need to know a filename to do this. 

-rwsr-xr-x    1 root     kmem       106344 Feb 23  16:42 /usr/bin/netstat

-rwxr-sr-x    1 root     kmem       106344 Feb 23  16:42 /usr/bin/netstat

-rwxr-xr-x    1 root     kmem       106344 Feb 23  16:42 /usr/bin/netstat

#!/bin/sh
#
 
echo hello

alias rm='rm -i';