[Fix #267] Fix psu on non-Mac OS X systems

modules/utility/init.zsh

@@ -169,6 +169,6 @@ function find-exec {
 
 # Displays user owned processes status.
 function psu {
-  ps -{U,u}" ${1:-$USER}" -o 'pid,%cpu,%mem,command' "${(@)argv[2,-1]}"
+  ps -U "${1:-$USER}" -o 'pid,%cpu,%mem,command' "${(@)argv[2,-1]}"
 }