fish-shell/fish-shell — pull request #1666 by critias (2014-09-06 19:36:38+00:00)
Title: Preexec 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 documentation as discussed here:
https://github.com/fish-shell/fish-shell/pull/1563

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
```