zsh/Completion/Unix/Command/_init_d

#compdef -p */(init|rc[0-9S]#).d/*

local magic cmds what script

_compskip=all

# This should probably be system specific...

script=$words[1]
[[ $script = */* ]] || script=/etc/init.d/$script

# If the file starts with `#!' we hope that this is a shell script
# and get lines looking like <space>foo|bar) with the words in $what.

what='(st(art|op|atus)|(force-|)re(start|load)|debug_(up|down)|dump(|_stats)|add|delete|clean|list)'

read -u0k 2 magic < $script && [[ $magic = '#!' ]] &&
    cmds=( ${${(j:|:s:|:)${(M)${(f)"$(< $script)"}:#[[:blank:]]#(\'|)${~what}(\|{~what})#(\'|)\)}}//[^a-z_]} )

# This would be the pattern to use every line of the form <space>foo).
# Some people say this might match too many lines...
#
#    cmds=( ${${(j:|:s:|:)${(M)${(f)"$(< $script)"}:#[[:blank:]]#(\'|)[a-z_|]##\'|)\)}}//[^a-z_]} )

(( $#cmds )) || zstyle -a ":completion:${curcontext}:commands" commands cmds ||
    cmds=(start stop)

_sub_commands $cmds