List of the most useful Ubuntu administration commands.
Package Management
List All Installed Packages
See exactly what is installed in your system,
dpkg --get-selections > installed-software.txt
The same list can also be used to install the same packages on another machine... Note I have not tested this command myself yet.
dpkg --set-selections < installed-software.txt dselect
Determine Package Program Belongs To
Find out what packages if any use the specified folder,
dpkg -S "/etc/ssl/certs" openssl, ca-certificates: /etc/ssl/certs
The package lookup will only work against the original binary. If it does not appear to work, check if the file you are referencing is actually a symbolic link and follow the links to the real binary file.
List all files relate to a package,
dpkg -L ca-certificates /. /etc /etc/ssl /etc/ssl/certs /etc/ca-certificates /etc/ca-certificates/update.d /usr /usr/sbin /usr/sbin/update-ca-certificates /usr/share /usr/share/ca-certificates ...
Determine if package is installed,
dpkg - l | grep -i upstart
Service Management
Upstart
Upstart is moving towards being the official service management utility. So not all services are yet converted to upstart. However, for the ones that are, it is very easy to use.
I'm still filling this out.
Determine if a service is upstart based,
sudo status servicename
hmm... does not work with Apache2 so that is not yet managed by upstart but sudo service apache2 status works..... so I wonder if service is better.
See list of upstart jobs running,
ls /etc/init/*.conf http://askubuntu.com/questions/42444/the-list-of-running-daemons #possibly upstart way http://askubuntu.com/questions/42444/the-list-of-running-daemons
update-rc.d
Apache for example is not yet moved to upstart. So to manage it, use update-rc.d,
sudo update-rc.d apache2 disable update-rc.d: warning: apache2 start runlevel arguments (none) do not match LSB Default-Start values (2 3 4 5) update-rc.d: warning: apache2 stop runlevel arguments (none) do not match LSB Default-Stop values (0 1 6) Disabling system startup links for /etc/init.d/apache2 ... Removing any system startup links for /etc/init.d/apache2 ... /etc/rc0.d/K09apache2 /etc/rc1.d/K09apache2 /etc/rc2.d/S91apache2 /etc/rc3.d/S91apache2 /etc/rc4.d/S91apache2 /etc/rc5.d/S91apache2 /etc/rc6.d/K09apache2 Adding system startup for /etc/init.d/apache2 ... /etc/rc0.d/K09apache2 -> ../init.d/apache2 /etc/rc1.d/K09apache2 -> ../init.d/apache2 /etc/rc6.d/K09apache2 -> ../init.d/apache2 /etc/rc2.d/K09apache2 -> ../init.d/apache2 /etc/rc3.d/K09apache2 -> ../init.d/apache2 /etc/rc4.d/K09apache2 -> ../init.d/apache2 /etc/rc5.d/K09apache2 -> ../init.d/apache2
Don't just try and manually remove symlinks from intit.d. Services will be enabled during package updates.
References
Start of good reading on upstart - http://askubuntu.com/questions/19320/whats-the-recommend-way-to-enable-disable-services
LSB (Linux Standard Base) way .... talks about legacy command and it's smart to figure it out - http://askubuntu.com/questions/6358/how-do-you-restart-apache