fish-shell/fish-shell — pull request #1563 by critias (2014-07-16 16:49:51+00:00)
Title: Added fish_preexec and fish_postexec event

Issue: https://github.com/fish-shell/fish-shell/issues/1549
Implemented a solution as event instead of a function call as discussed here: https://github.com/fish-shell/fish-shell/pull/1550
Added a postexec event as well for completeness

Usage:
```
function preexec_test --on-event fish_preexec
echo preexec handler: $argv
end

function postexec_test --on-event fish_postexec
echo postexec handler: $argv
end
```