List of the most useful Ubuntu administration commands.
List All Installed Packages
See exactly what is installed in your system,
The same list can also be used to install the same packages on another machine... Note I have not tested this command myself yet.
Determine Package Program Belongs To
Find out what packages if any use the specified folder,
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,
Determine if package is installed,
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,
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,
Apache for example is not yet moved to upstart. So to manage it, use update-rc.d,
Don't just try and manually remove symlinks from intit.d. Services will be enabled during package updates.
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