You’re too lazy to write touch foo.txt? Well, you can avoid it thanks to the following hack with the : command:

:> foo.txt

And a bonus! You can also use : to ignore the output of a shell command:

: `command`

But that isn’t very useful in practice - the command output is sent as command-line parameters to :, which means this hack is pretty heavy if the command outputs a lot of stuff.

(Source)