Happy π day!
I've finally made myself a compose-key shortcut for π so I can type it easily.
I added this line to the bottom of my ~/.XCompose file:
<Multi_key> <p> <i> : "π"
(how to turn on the compose key on Ubuntu: help.ubuntu.com/community/Comp…)
In reply to @christianp
Oh! I had wondered about all the <dead_greek> entries in .XCompose.
It turns out I can map a key to produce <dead_greek>, and type any Greek letter easily.
I mapped the "menu" key next to my right Ctrl:
xmodmap -e 'keycode 135 = dead_greek'
Then <dead_greek> <p> gets π
In reply to @christianp
update: I have just accidentally typed Τ, which is not the letter T. It's capital tau. Which is visually indistinguishable from latin T