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Debian

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1. Sync your computers time with an ntp server
2. Typing Game
3. Mount Samba Network Drive
4. Default text browser
5. BASH script to create virtual host
6. FFmepg with mp3 support through LAME
7. Enabling CGI
8. Format a drive
9. Imagemagick error when starting PHP
10. Using the unstable branch
11. sudo: unable to resolve host
12. Enabling root on Ubuntu
13. Setting up stunnel
1. 13.1 Installing
2. 13.2 Enabling stunnel
3. 13.3 Create you certificate with openssl
4. 13.4 Start your stunnel server
5. 13.5 Example of setting up remote desktop for stunnel
6. 13.6 References
14. How to install a specific version of a package
1. 14.1 See what versions are available
2. 14.2 Install the specific version
15. Setting scripts to start at different run levels
16. Apache 2 with SSL
1. 16.1 Create a Certificate
2. 16.2 Install Module
3. 16.3 Create virtualhost
4. 16.4 Enable SSL virtualhost
5. 16.5 Restart Apache server
6. 16.6 Add other virtual hosts
7. 16.7 My Sample Virtual Hosts /etc/apache2/httpd.conf
8. 16.8 Reference
17. Span across two monitors (dual monitors)
1. 17.1 See if your system can use xrandr by issuing the command
2. 17.2 Find your screens with the command
3. 17.3 Clone your screens
4. 17.4 Turn the second monitor off (One on right)
5. 17.5 Make sure you have setup the Virtual width of your monitors
6. 17.6 Turn back on your right monitor with spanning enabled.
18. Turn off that annoying pc speaker beep
19. Get your current users id number
20. Add a user to a group
21. Install failed with Errors were encountered while processing: acpid
1. 21.1 Another example
22. Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
23. Setting my PS1 and aliases for BASH
24. apt-get won't install because of unmet dependencies
25. Activating modules with Apache2
26. shfs
1. 26.1 Installing shfs
2. 26.2 Running shfs
3. 26.3 shfsmount: shfs filesystem not supported by the kernel
27. Finding information about a package
28. How to search for a package to install
29. How to install a package
30. How to activate root user in Ubuntu
31. Resynchronize the package index for apt-get
32. apt-get keeps requesting a cdrom
33. Installing kernel header files
34. Undocumented Ideas
35. Page Comments (Click to edit)

1. Sync your computers time with an ntp server

$ apt-get install ntpdate
$ crontab -e

Add the following to your crontab,

0 0 * * * ntpdate -b north-america.pool.ntp.org >> /dev/null

You can find other servers here, http://support.ntp.org/bin/view/Servers/NTPPoolServers », or just http://www.ntp.org ».

2. Typing Game

If you want to test out your typing skills, or go head to head with an opponent, try out typespeed

$ apt-get install typespeed

To run it, type,

$ /usr/games/typespeed

3. Mount Samba Network Drive

I'm mount a Sans Digital MobileNAS MN2L. I created a mount named sarge. To mount sarge in Ubuntu, I use the following command.

$ mount -t cifs //ip_address/sarge /media/sarge -o username=joe,password=foo,defaults

4. Default text browser

$ w3m http://www.google.com

5. BASH script to create virtual host

#!/bin/bash

echo "Enter a domain (e.g. example.com):";
read domain;
echo ""
echo "Enter a virtual host name (e.g. dev, as in dev.example.com
Just enter only the virtual host name)"
read vhname
echo ""

### Check to see if $domain exists
if ! grep "${vhname}.${domain}" /etc/apache2/httpd.conf >> /dev/null; then
        echo "${vhname}.${domain} will be created"
        echo "Are you sure you want to do this?"
        read q
        if [[ "${q}" == "yes" ]] || [[ "${q}" == "y" ]]; then
                cp /etc/apache2/httpd.conf /etc/apache2/httpd.conf.`date +%Y%m%d%H%M%S`

                if [[ ! -e /var/www/${vhname} ]]; then mkdir /var/www/${vhname}; fi
                if [[ ! -e /var/www/${vhname}/htdocs ]]; then mkdir /var/www/${vhname}/htdocs; fi

                echo "
### ${vhname}.${domain}
<Directory /var/www/${vhname}/htdocs>
        Options All MultiViews ExecCGI
        AddHandler cgi-script cgi pl
        AllowOverride All
        Order allow,deny
        Allow from all
</Directory>
<VirtualHost *:80>
        ServerName ${vhname}.${domain}
        DocumentRoot /var/www/${vhname}/htdocs
        # Possible values include: debug, info, notice, warn, error, crit,
        # alert, emerg.
        LogLevel warn
        CustomLog /var/log/apache2/access.log combined
</VirtualHost>
</VirtualHost>" >> /etc/apache2/httpd.conf

                echo "Testing configuration"
                apache2ctl configtest
                echo "Would you like me to restart the server?"
                read q
                if [[ "${q}" == "yes" ]] || [[ "${q}" == "y" ]]; then
                        apache2ctl restart
                fi
        fi
else
        echo "${domain} already exists"
fi

6. FFmepg with mp3 support through LAME

First, add the following contents to /etc/apt/sources.list.

deb http://www.debian-multimedia.org/ etch main
deb-src http://www.debian-multimedia.org/ etch main

Then issue the following command. Note, it may end in error - see the Q and A below for help.

$ sudo apt-get update

The following is a direct quote from the FAQ page at http://www.debian-multimedia.org ».

Q. Why apt-get doesn't find this public key : NO_PUBKEY 07DC563D1F41B907 ?
A. Install the debian-multimedia-keyring package with apt-get install debian-multimedia-keyring or with dpkg -i debian-multimedia-keyring (click on the link to download the package).

Now you should be able to install FFmpeg with,

$ sudo apt-get install ffmpeg

7. Enabling CGI

Inside of a <Directory>, make sure you have the following set. I'm doing this for each virtual host.

Options ExecCGI
AddHandler cgi-script cgi pl

Also, I installed libapache2-mod-perl2.

8. Format a drive

To format a drive as ext3, just use the following, assuming that your drive is /dev/sdb.

$ sudo mkfs.ext3 /dev/sdb1

Now you can change it's label with,

$ sudo e2label /dev/sdb1 your_label

9. Imagemagick error when starting PHP

PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20060613+lfs/imagick.so' - libWand.so.9: cannot open shared object file: No such file or directory in Unknown on line 0

Just issue the following commands,

# ln -s /usr/lib/libWand.so.10.0.9 /usr/lib/libWand.so.9
# ln -s /usr/lib/libMagick.so.10.0.9 /usr/lib/libMagick.so.9

or substitute the appropriate library in place of 10.0.9.

10. Using the unstable branch

The unstable branch contains the newest versions of software. I've used it for packages like xmoto and virtualbox where I want the latest version.

Just add the following two lines to /etc/apt/sources.list

deb http://ftp.uwsg.indiana.edu/linux/debian/ unstable main contrib non-free
deb-src http://ftp.uwsg.indiana.edu/linux/debian/ unstable main contrib non-free

You can change the mirror to something other than indiana.edu if you want. I'm not sure what they are though.

11. `sudo: unable to resolve host`

If you ever get a message like, sudo: unable to resolve host, this may be if you changed your hostname with hostname -v newhostname or any other reason I'm not aware of.

Anyway, open /etc/hosts and make sure your new hostname matches the one in there. Your old one may be in /etc/hosts and needs to be manually updated.

Since you can't use sudo to do this, you will have to become root. Hopefully if you're using Ubuntu you enabled your root account, otherwise I'm not sure how you'll do this. See Enabling root on Ubuntu below.

12. Enabling `root` on Ubuntu

Just open a terminal and do the following,

$ sudo su -
$ passwd

Enter a password once it prompts you and confirm. root is now enabled. You can type exit and hit enter. Then try the command su and see if you can become root.

13. Setting up stunnel

13.1 Installing

$ sudo apt-get install stunnel

13.2 Enabling stunnel

$ vi /etc/default/stunnel4

Change the line,

ENABLED=0

ENABLED=1

13.3 Create you certificate with openssl

$ openssl req -new -out mail.pem -keyout mail.pem -nodes -x509 -days 365

Where ever your /etc/stunnel/stunnel.conf file is pointing to mail.pem is where you should put this file. Mine points to /etc/stunnel/mail.pem.

13.4 Start your stunnel server

$ sudo /etc/init.d/stunnel4 start

If you get an error like You should check that you have specified the pid= in you configuration file, open up /etc/stunnel/stunnel.conf and comment out these services that may be enabled by default.

;[pop3s]
;accept  = 995
;connect = 110

;[imaps]
;accept  = 993
;connect = 143

;[ssmtp]
;accept  = 465
;connect = 25

13.5 Example of setting up remote desktop for stunnel

Edit your /etc/stunnel/stunnel.conf.

Add the contents,

[rdp]
accept = 1234
connect = 123.123.123.123:22

and uncomment the line that says ;client = yes. This should be done on the client side. Restart stunnel: /etc/init.d/stunnel4 restart.

The accept variable (port) can be anything. I think maybe greater than 1000, but I'm not sure. The connect variable should be the host you are trying to connect to with <colon><port_number> appended to it.

On the server side, you would do something similar. Just add to your stunnel.conf

[rdp]
accept = 22
connect = 3389

and start the stunnel server.

Now we need to connect to the remote desktop. On the client, since we set the accept port to 1234 and mapped that to 123.123.123.123:22 the server, we will connect to the remote desktop server from the client itself. Just issue the command,

$ rdesktop localhost:1234

This looks in the stunnel.conf on the client side, finds the service that accepts port 1234, and then actually performs the connect which is to host 123.123.123.123 on port 22. On the server end, stunnel gets a request on port 22 and says to actually connect to port 3389, the one remote desktop is running on.

Note, my router at home has another server using port 22 for ssh, so I used port 23 instead. Works the same.

13.6 References

14. How to install a specific version of a package

14.1 See what versions are available

To see what versions of a package are available, use the command

# apt-cache show <package_name>

This will give you a description of the package and some other stuff like md5 and sha hashs.

You can also run,

# apt-cache showpkg <package_name>

and that will show a little less information. Try them both.

14.2 Install the specific version

Once you have your version number, you can use the following command,

# apt-get install <package_name>=<version#>

An example would be version 0.45.1-1 of inkscape.

# apt-cache show inkscape
# apt-cache showpkg inkscape
# apt-get install inkscape=0.45.1-1

15. Setting scripts to start at different run levels

Say you want to have a program that's in /etc/init.d startup at boot time or another run level, you will be making a symbolic link from /etc/init.d/yourprogram to /etc/rc<some_integer>.d/S<some_2_digit_integer>yourprogram.

The run level (<some_integer>) can be one of the following,

 0 - System Halt
 1 - Single user
 2 - Full multi-user mode (Default)
 3-5 - Same as 2
 6 - System Reboot

In the /etc/rc<some_integer>.d directory, if the program begins with an S the script is active. If you want to deactivate it, just move it to the same name, but instead of an S make it a K.

Here's an example,

$ ls -l /etc/rc3.d/
lrwxrwxrwx 1 root root  13 2008-04-13 22:16 S16ssh -> ../init.d/ssh

To actually make that symbolic link, you can execute the command,

# ln -s /etc/init.d/ssh /etc/rc3.d/S16ssh

Basically, you choose the integer which determines the start order, and prefix it with an S so that it is active.

To make it inactive, just run,

# mv /etc/rc3.d/S16ssh /etc/rc3.d/K16ssh

16. Apache 2 with SSL

I did this on Ubuntu 8.04 (Hardy), but I'm sure it will work on the equivalent Debian system. I installed the server version, but the Desktop should be fine also.

I installed LAMP (Linux Apache MySQL and PHP), or you can install apache2

$ sudo apt-get install apache2

16.1 Create a Certificate

$ sudo apt-get install ssl-cert
$ sudo mkdir /etc/apache2/ssl
$ sudo make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache.pem

16.2 Install Module

$ sudo a2enmod ssl
$ sudo /etc/init.d/apache2 force-reload

16.3 Create virtualhost

Make a copy of the default VirtualHost

$ sudo cp /etc/apache2/sites-available/default /etc/apache2/sites-available/ssl

Modify /etc/apache2/sites-available/ssl so that you have,

NameVirtualHost *:443

and

<VirtualHost *:443>
SSLEngine On
SSLCertificateFile /etc/apache2/ssl/apache.pem

.
.
.

</VirtualHost>

16.4 Enable SSL virtualhost

$ sudo a2ensite ssl
$ sudo /etc/init.d/apache2 reload

Modify /etc/apache2/sites-available/default so that you change your NameVirtualHost and any other virtual hosts to *:80 as in the next two lines.

NameVirtualHost *:80
<VirtualHost *:80>

16.5 Restart Apache server

$ sudo /etc/init.d/apache2 restart

16.6 Add other virtual hosts

I add mine to the file /etc/apache2/httpd.conf, but you can add them elsewhere -- probably somewhere more appropriate.

Here's an example.

<VirtualHost *:443>
ServerName my.example.com
DocumentRoot /var/www/myexample/htdocs
SSLEngine On
SSLCertificateFile /etc/apache2/ssl/apache.pem
</VirtualHost>

16.7 My Sample Virtual Hosts `/etc/apache2/httpd.conf`

<Directory /var/www/localhost/htdocs>
Options All MultiViews
AllowOverride All
Order allow,deny
Allow from all
</Directory>
<VirtualHost *:80>
ServerName www.example.com
DocumentRoot /var/www/localhost/htdocs
LogLevel warn
CustomLog /var/log/apache2/access.log combined
</VirtualHost>
<VirtualHost *:443>
ServerName www.example.com
DocumentRoot /var/www/localhost/htdocs
SSLEngine On
SSLCertificateFile /etc/apache2/ssl/apache.pem
LogLevel warn
CustomLog /var/log/apache2/access.log combined
</VirtualHost>

16.8 Reference

https://help.ubuntu.com/community/forum/server/apache2/SSL »

17. Span across two monitors (dual monitors)

17.1 See if your system can use `xrandr` by issuing the command

$ xrandr -v

17.2 Find your screens with the command

$ xrandr -q

Substitute whatever comes out of xrandr -q where it says XXX connected. My XXX was DVI-0 and DVI-1. When we turn one of them off, you'll see which is which. Just run the next command of cloning to turn them both back on.

17.3 Clone your screens

$  xrandr --output DVI-0 --auto --output DVI-1 --auto --same-as DVI-0

17.4 Turn the second monitor off (One on right)

$  xrandr  --output DVI-1 --off

17.5 Make sure you have setup the Virtual width of your monitors

I have 2 1280x1024 monitors. That means my virtual resolution is 2560x1024. You'll want to add that to your /etc/X11/xorg.conf file.

Just add it in the section that looks like mine as follows. It's the line with Virtual 2560 1024.

Section "Screen"
	Identifier	"Default Screen"
	Device		"ATI Technologies Inc RV380 [Radeon X600 (PCIE)]"
	Monitor		"DELL 1907FP"
	DefaultDepth	24
	SubSection "Display"
		Depth		24
		Modes		"1280x1024" "1152x864" "1024x768" "800x600" "720x400" "640x480"
		Virtual		2560 1024
	EndSubSection
EndSection

Download » my entire xorg.conf file to see what else is going on.

I'm also running on a Dell Optiplex GX620 with a PCI card that splits my ATI Radeon into to DVI monitors. I have some funky DVI Y splitter adapter thing. I don't know what it is, but I can explain it more if you like. My email is in the footer of this page.

17.6 Turn back on your right monitor with spanning enabled.

$ xrandr --output DVI-1 --auto --right-of DVI-0

That's it, none of that fancy MergeFB or TwinView or Xinerama ... etc. You may however have to issue those commands if you logout or reboot, I'm not sure. I'm definitely not sure how to make it happen by default. You may be able to create a startup item that runs those xrandr commands for you, but I haven't had the time to do that yet. Maybe later...

18. Turn off that annoying pc speaker beep

Either run,

# rmmod pcspkr

or black list it so that the kernel will never load the module by adding the following line to /etc/modprobe.d/blacklist

blacklist pcspkr

19. Get your current users id number

This can also be found in the line that contains your username in /etc/passwd, or you can issue this command,

# id -u

20. Add a user to a group

You can either append the username to the group entry in /etc/group or you can use the following command.

# adduser wsams fuse

21. Install failed with Errors were encountered while processing: `acpid`

I'm sure there are plenty of other packages that fail with a similar error.

I was trying to do a apt-get dist-upgrade after switching from etch to unstable. It was hanging on acpid.

Here is one of the errors I was getting,

Setting up acpid (1.0.6-5) ...
tar: Removing leading `/' from member names
tar: /etc/logrotate.d/acpid*: Cannot stat: No such file or directory
tar: /var/log/acpid*: Cannot stat: No such file or directory
tar: /etc/acpi/powerbtn.sh*: Cannot stat: No such file or directory
tar: /etc/acpi/events/powerbtn*: Cannot stat: No such file or directory
tar: Error exit delayed from previous errors
Stopping Hardware abstraction layer: hald.
Loading ACPI modules....
Starting Advanced Configuration and Power Interface daemon...invoke-rc.d: initscript acpid, action "start" failed.
dpkg: error processing acpid (--configure):
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
 acpid
E: Sub-process /usr/bin/dpkg returned an error code (1)

Anyway, after some searching, I found three commands that should remedy this situation. (Perform as root or with sudo.)

# /etc/init.d/acpid stop
# dpkg --configure acpid
# dpkg --configure -a

I would assume if another program was failing, you could substitute that package name for acpid in the three commands above.

I did as this guy said, and stopped acpid a couple times to make sure it stopped.

21.1 Another example

Okay, I ran into this again with libdjvulibre21. It couldn't be installed because libdjvulibre15 was installed. Basically, you remove 15 and continue the install to install 21. Below are the commands. Found at http://bugs.debian.org ».

# dpkg -P libdjvulibre15
# apt-get -f install

http://ubuntuforums.org/archive/index.php/t-416676.html »

22. Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName

Okay, this is an easy fix for Apache2 in Debian. I'm using 4.0r2 during the time of this writing.

Let's say your website is at www.example.com. You need to setup your hostname to this.

Issue the following commands.

# echo "www.example.com" > /etc/hostname
# hostname -F /etc/hostname

Now restart Apache.

I also did,

# hostname -v www.example.com

but that might not be necessary. The above two commands may set that based on what you put in /etc/hostname. I bet hostname -F /etc/hostname is the same as hostname -v www.example.com.

23. Setting my PS1 and aliases for BASH

In Debian as of 4.0r2, you can set a master bashrc file at /etc/bash.bashrc.

My .bashrc file looks in partial like,

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
xterm-color)
    PS1='\n-----------------------------\n\t ${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
    ;;
*)
    PS1='\n-----------------------------\n\t ${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
    ;;
esac

alias ls="ls -F"
alias ll="ls -l"
alias ltr="ls -ltr"
alias rm="rm -i"
alias mv="mv -i"
alias cp="cp -i"
alias pico="pico -r3000"
alias htdocs="cd /var/www"

On another machine (Redhat) I have this PS1 setup.

PS1="\n-----------------------------\[\e]0;\w\a\]\n\t \[\e[32m\]\u@\h \[\e[33m\]\w\[\e[0m\]\n\$ "

24. `apt-get` won't install because of unmet dependencies

Basically, what happened to me was I changed my /etc/apt/sources.list file to point to different repositories, and all of a sudden libc6 wouldn't install. It kept giving me the message, try apt-get -f install. Well, that didn't work. By the way, I was trying to install Xmoto », and there was some unmet dependency or something, and that's what sparked the libc6 installation problem. It also said it found a service running, on my machine, it was gdm. It said stop the service first, I did, and it didn't matter, it still wouldn't install libc6.

After a while, I ended up trying this.

I changed my branch from unstable, to lenny. That's in /etc/apt/sources.list, and it looks similar to this.

It was

deb http://www.example.com/debian/ unstable main contrib non-free

I changed that line to

deb http://www.example.com/debian/ lenny main contrib non-free

did a,

# apt-get update

then I did

# apt-get install libc6

and it installed. Note, it still said gdm was running and that I should stop the service before installing. This time I didn't do it, and nothing happened. It installed with no problems. To be safe, you might want to reboot your machine after this.

Then I went back and changed lenny back to unstable, did a apt-get update and went about my business installing Xmoto ».

25. Activating modules with Apache2

In Apache2 on debian, all of the available modules are in the directory /etc/apache2/mods-available and all of the modules that are enabled are in the directory /etc/apache2/mods-enabled.

To activate a module like rewrite, just create a symbolic link from the file in mods-available to mods-enabled.

Here's how to do that for the rewrite module, but the others are identical.

# cd /etc/apache2/mods-enabled
# ln -s ../mods-available/rewrite.load .

Restart the apache server now.

# /etc/init.d/apache2 restart

26. `shfs`

26.1 Installing shfs

# apt-get install shfs-utils

26.2 Running shfs

Here's an example of mounting the directory /path/to/remote/directory/to/mount on the host www.example.com to the local directory /path/to/local/mountpoint.

shfsmount -o uid=myuser,gid=mygroup username@www.example.com:/path/to/remote/directory/to/mount /path/to/local/mountpoint

26.3 shfsmount: shfs filesystem not supported by the kernel

To resolve this issue, run the following commands.

Install the shfs-source package and all its dependencies.

# apt-get install shfs-source

Install gcc if you don't have it already

# apt-get install gcc

Install the linux-headers package that matches your kernel version.

apt-get install linux-headers-$(uname -r)

The shfs-source package should have forced installation of module-assistant, so now:

# module-assistant build shfs
# module-assistant install shfs

You may want to restart your system, but this worked without restarting for me.

27. Finding information about a package

Issue the command

# apt-cache show <package_name>

This will show a lot of stuff about the package, including the package version number.

28. How to search for a package to install