#compdef comm gcomm

local -a args

args=(
  '-1[suppress lines unique to first file]'
  '-2[suppress lines unique to second file]'
  '-3[suppress lines that appear in both files]'
  '1:file to compare:_files'
  '2:file to compare:_files'
)

if _pick_variant gnu=GNU unix --version; then
  args+=(
    '(--nocheck-order)--check-order[check input is correctly sorted]'
    "(--check-order)--nocheck-order[don't check input is correctly sorted]"
    '--output-delimiter=:delimiter'
    '(- : *)--version[display version information]'
    '(- : *)--help[display help information]'
  )
elif [[ $OSTYPE = (freebsd|dragonfly|darwin)* ]]; then
  args+=( '-i[case insensitive comparison of lines]' )
elif [[ $OSTYPE = (openbsd|netbsd)* ]]; then
  args+=( '-f[case insensitive comparison of lines]' )
fi

_arguments -s $args