An Ubuntu live CD can save a regular sysadmin alot of trouble. It boots an entire Ubuntu Linux system right off the CD, without touching the harddrive. It can then be used for backups without requiring the system to even have an operating system.
- Note: Alot of ubuntu specific information can be found on the ubuntu wiki and the ubuntu documentation.
One-liner password generator Edit
Generates 40 sets of 12 characters of small and large caps alphanum characters and includes punctuation characters:
for i in `seq 1 40`; do tr -dc "[:alnum:][:punct:]" < /dev/urandom | head -c 12; echo \n; done
Join AD domain Edit
Pipe text to and from the clipboard Edit
You can pipe the output of ls to the clipboard:
ls | xclip -selection c
And then you can output the clipboard contents:
xclip -o -selection c
Encrypted boot partition Edit
In ubuntu 8.04 you can encrypt the system partition by installing from the alternate install cd. The installation guide will give you the option to encrypt the drive it installs to.
Install on a usb drive Edit
Restore a grub MBR Edit
The CLI way Edit
Find the partition that has the root of your linux installation (usually the only one with partition ID 83):
sudo fdisk -l
Mount it and install grub on the MBR (replace sda and sda1 with the appropriate in your case):
sudo mkdir /mnt/hd sudo mount -t ext3 /dev/sda1 /mnt/hd sudo grub-install --root-directory=/mnt/hd /dev/sda
Network speed and duplex Edit
Show the status of the network cards' current speed and duplex setting and whether it was auto-negotiated:
Show each network cards capabilities:
sudo ethtool eth0; sudo ethtool eth1
Change speed and duplex Edit
Set eth0 to 10half manually (doesn't last a reboot):
ethtool -s eth0 speed 10 duplex half autoneg off
To set speed and duplex that will last a reboot, add the following to your /etc/network/interfaces in the stanza for your network card:
pre-up ethtool -s eth0 speed 10 duplex half autoneg off
The CLI wayEdit
This small script counts the seconds of downtime (remember to set the IP address):
i=0 while [ true ]; do ping -W1 -c1 IP_address 1> /dev/null if [ $? -eq 0 ]; then echo Running... sleep 1 else ((i++)) echo Error. "Not running! Downtime: $i seconds" fi done
Date format Edit
Gnome clock applet Edit
You can set the clock applet's format to something custom with these commands (this makes it the ISO standard date and time format - it follows PHP's strftime format):
gconftool-2 --set /apps/panel/applets/clock_screen0/prefs/custom_format --type string "%Y-%m-%d %H:%M" gconftool-2 --set /apps/panel/applets/clock_screen0/prefs/format --type string "custom"
Unity clock applet Edit
Ubuntu 11.04 introduced Unity, which has different applets than Gnome. The date format can be set in a similar way to Gnome:
gsettings set com.canonical.indicator.datetime custom-time-format "'%F %H:%M'" gsettings set com.canonical.indicator.datetime time-format "'custom'"
System setting Edit
You can change the default date format in Ubuntu to the ISO 8601 format.
- First make sure the locale definition files are compiled:
sudo localedef -f UTF-8 -i en_DK en_DK.UTF-8
- Then edit /etc/environment and add:
If you want to avoid the Setting locale failed error, when SSH'ing to servers without the en_DK.UTF-8 locale generated:
- Comment out this line in /etc/ssh/ssh_config
SendEnv LANG LC_*
Your locale settings will then not be brought with you to remote servers.
SSL certificate Edit
Adding a self-signed certificate:
certutil -d sql:$HOME/.pki/nssdb -A -t "P,," -n <certificate nickname> -i <certificate filename>
Listing added certificates:
certutil -d sql:$HOME/.pki/nssdb -L
Deleting an added certificate:
certutil -d sql:$HOME/.pki/nssdb -D -n <certificate nickname>
Cursor size Edit
Set the cursor size factor with this command:
gsettings set com.canonical.Unity.Interface cursor-scale-factor 2