SaltyCrane Blog

Notes on Python, Django, and web development on Ubuntu Linux

Ubuntu notes

Date: 2009-03-25 | Modified: 2011-12-19 | Tags: notestoself, ubuntu

Boot process

What are the stages of the boot process?
1. BIOS
2. Master Boot Record
3. Bootloader (LILO, GRUB)
4. Kernel
5. init
6. Run Levels
Where is the GRUB menu list?
/boot/grub/menu.lst
How do I get rid of Ubuntu splash screen / progress bar and show scrolling text?
Remove quiet and splash from "kernel" line in /boot/grub/menu.lst

Run levels

What are the run levels for Ubuntu?
1: single user
2: default
3-5: same as 2
6: reboot
Where can I find the default startup programs for run level 2?
/etc/rc2.d
How do I update the symbolic links in /etc/rc?.d?
Use update-rc.d. For help, man update-rc.d.
Where is the default run level set in Ubuntu?
/etc/event.d/rc-default

Xsessions

Where is another location for startup programs?
/etc/X11/Xsession.d

Restarting

What are some alternatives to rebooting?
1. Restart the display manager, gdm
  sudo /etc/init.d/gdm restart or CTRL+ALT+BACKSPACE
2. Switch to runlevel 1 then back to runlevel 2
  sudo telinit 1 then telinit 2 (this didn't work for me; I wasn't able to get to runlevel 1.)
3. This article has a lot of good tips including Alt+SysReq+"Raising Skinny Elephants Is Utterly Boring" - http://www.linuxclues.com/articles/09.htm
How can I reboot?
reboot or CTRL+ALT+DEL

Keeping Ubuntu time up to date

I would think Ubuntu would install something to keep the system clock from drifting, but it seems they haven't. There are at least 2 options: ntpdate and ntpd. Ntpdate is used from a cron script to sync the time once a day. Ntpd runs as a daemon and ajusts the time continually but it costs resources. On my machine, using ps -e -O rss | grep ntpd, I got 1.3 MB of memory use. Here is how to install ntpd:

sudo apt-get install ntp

The ntp config file is located at: /etc/ntp.conf

Reference: https://help.ubuntu.com/9.04/serverguide/C/NTP.html

My /etc/apt/sources.list

This sources.list includes security, updates, and proposed (but not backports) and source for the main, restricted, universe, and multiverse repositories.

deb http://archive.ubuntu.com/ubuntu/ jaunty main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ jaunty-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-security main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ jaunty-updates restricted main universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-updates restricted main universe multiverse

deb http://archive.ubuntu.com/ubuntu/ jaunty-proposed restricted main multiverse universe
deb-src http://archive.ubuntu.com/ubuntu/ jaunty-proposed restricted main multiverse universe

My filesystem changes

For wmii:

sudo ln -s /usr/include/freetype2/freetype /usr/include/freetype

System config file changes:

These changes apply to Ubuntu Karmic

Disable xsplash before session load: Comment out the following from /etc/gdm/PreSession/Default:
```
if [ -x '/usr/bin/xsplash' ];
then
        /usr/bin/xsplash --daemon
fi
```
To run ~/.xsession from gdm: Create a '.desktop' file in '/usr/share/xsessions' [owned by root:root with permissions 644] whose 'Exec' entry is '/etc/X11/Xsession'.

How to show what you've installed with apt-get

Haven't found a way that I'm happy with yet. Here are some options:

sudo apt-get install apt-show-versions
apt-show-versions

```
dpkg --get-selections
```
```
dpkg -l 
```
```
cat /var/log/dpkg.log | grep installed 
```

Sound troubleshooting

Make sure speakers are plugged in / power strip on. (For some reason, the power to my speakers keeps going out.
Run gnome-volume-control. Make sure volume is up and not muted. (For some reason on Karmic this resets to mute on restart.)

Skype microphone troubleshooting

Running Skype 2.1.0.47-1 on Ubuntu Karmic

Run gnome-volume-control. Select Microphone 1. Raise the volume up to almost Max.
(Testing can be done with gnome-sound-recorder.)

Flash

Karmic w/ Firefox 3.5.5
Can't click in Flash - http://ubuntuforums.org/showthread.php?t=1314910

Emacs keybindings

Copy /usr/share/themes/Emacs/gtk-2.0-key/gtkrc to ~/.gtkrc-2.0. Edit as necessary.

(Hardware) System Information

sudo apt-get install sysinfo

custom xsession

Edit /usr/share/xsessions/user.desktop

[Desktop Entry]
Name=~/.xsession
Comment=User's .xsession
Exec=/etc/X11/Xsession
TryExec=/etc/X11/Xsession
Icon=
Type=Application

Can't create test file error

Trying to move datadir from /var/lib/mysql to /mnt/mysql-data on EC2

http://ubuntuforums.org/showthread.php?t=782224

Had to edit /etc/apparmor.d/usr.sbin.mysqld

Troubleshooting X freezes

Thinkpad W510 suspend

http://math.umons.ac.be/an/W510/#ACPI
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/522998
For Ubuntu 10.10:
/etc/pm/config.d/unload_modules

SUSPEND_MODULES="xhci_hcd"

Note: in 10.04, I had "xhci" instead of "xhci_hcd"

Cisco VPN¶

$ sudo apt-get install network-manager-vpnc

Click on network manager icon in gnome-panel
VPN Connections -> Cofigure VPN...
Import
Select file from my company
Set user name
Apply
Close

Restart newtork-manager

$ sudo /etc/init.d/network-manager restart

Click on network manager icon in gnome-panel
VPN Connections -> My Company
Enter password
Done

VPN change to gain access to important stuff on our network¶

 - click network icon
 - "VPN Connections" > "Configure VPN..."
 - highlight "My Company VPN"
 - "Edit"
 - "IPv4 Settings" tab
 - "Routes..."
 - uncheck "Use this connection only for resources on its network"
 - "OK"
 - "Apply"
 - "Close"

When the above vpn setup didn't work with my Verizon mifi¶

...using vpnc from the command line worked: http://www.debuntu.org/how-to-connect-to-a-cisco-vpn-using-vpnc See also: http://www.chicagotech.net/routingissuesonvpn.htm.

Set the timezone on a server¶

run as root

# dpkg-reconfigure tzdata

Set the hostname on a server¶