fish-shell/share/functions/__fish_complete_proc.fish

function __fish_complete_proc --description 'Complete by list of running processes'
	# Our function runs ps, followed by a massive list of commands passed to sed
	set -l ps_cmd
	set -l sed_cmds
	if test (uname) = Linux
		# comm and ucomm return a truncated name, so parse it from the command line field,
		# which means we have to trim off the arguments.
		# Unfortunately, it doesn't seem to escape spaces - so we can't distinguish
		# between the command name, and the first argument. Still, processes with spaces
		# in the name seem more common on OS X than on Linux, so prefer to parse out the
		# command line rather than using the stat data.
		# If the command line is unavailable, you get the stat data in brackets - so
		# parse out brackets too.
		set ps_cmd 'ps -A -o command'
		
		# Erase everything after the first space
		set sed_cmds $sed_cmds 's/ .*//'
		
		# Erases weird stuff Linux gives like kworker/0:0
		set sed_cmds $sed_cmds 's|/[0-9]:[0-9]]$||g'
		
		# Retain the last path component only
		set sed_cmds $sed_cmds 's|.*/||g'
		
		# Strip off square brackets. Cute, huh?
		set sed_cmds $sed_cmds 's/[][]//g'
		
		# Erase things that are just numbers
		set sed_cmds $sed_cmds 's/^[0-9]*$//'
	else
		# OS X, BSD. Preserve leading spaces.
		set ps_cmd 'ps axc -o comm'
		
		# Delete parenthesized (zombie) processes
		set sed_cmds $sed_cmds '/(.*)/d'	
	end
	
	# Append sed command to delete first line (the header)
	set sed_cmds $sed_cmds '1d'
	
	# Append sed commands to delete leading dashes and trailing spaces
	# In principle, commands may have trailing spaces, but ps emits space padding on OS X
	set sed_cmds $sed_cmds 's/^-//' 's/ *$//'
	
	# Run ps, pipe it through our massive set of sed commands, then sort and unique
	eval $ps_cmd | sed '-e '$sed_cmds | sort -u
end