How often have you typed a command in the Linux Shell, after which you're finding out you left out Sudo to the whole deal? With a bit of luck you're getting an error. Worst case scenario is editing a read only config file because of the lack of permissions. This happens to me a lot, so i'll share the best solution I can think of to correct it.

The "!!" syntax tells Bash to pull out the last command, with the possibility of adding a prefix or suffix. This means you can add " | more " to the last command by typing " !! | more ". You can also add the forgotten sudo to the command by typing " sudo !! ".

Try this as an example:

vi /etc/php5/apache2/php.ini

Which results in editing a config file you can't save. This is the solution:

sudo !!

You'll see the command you typed earlier right away, with the sudo you added, and the password prompt appears.

This is what you'll see:

tim@bytemods:~$ vi /etc/php5/apache2/php.ini

tim@bytemods:~$ sudo !!

sudo vi /etc/php5/apache2/php.ini

Password: