`hash -r` to rehash an executable that previously was not found and does now exist on your path

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Unicode character insertion:

`CTRL-SHIFT-U`

* `e 9` e acute

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To determine your exact Ubuntu version:

`lsb_release -a`

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To install a Debian package from the command-line:

`sudo dpkg -i /path/to/deb/file`

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Changing timezone on an Ubuntu box

`sudo timedatectl set-timezone 'Europe/London'`

List the current timezone information with:
`timedatectl`

See this for further reference:
http://askubuntu.com/a/594186