[7m Word Language [0;0m

  [Quotes]        quotes        'abc'  $'\n'  "$var"
  [Substitutions] com-sub       $(command)   `command`
                  var-sub       ${var}   $0   $9   
                  arith-sub     $((1 + 2))
                  tilde-sub     ~/src
                  proc-sub      diff <(sort L.txt) <(sort R.txt)
  [Var Ops]       op-test       ${x:-default}  
                  op-unary      ${x%%suffix}  etc.
                  op-str        ${x//y/z}
                  op-slice      ${a[@]:0:1}
                  op-format     ${x@P}
  [Oil Word]      inline-call   $strfunc(x, y) @arrayfunc(z)
                  splice        @array @ARGV
                  X oil-printf  ${x %.3f}
                  X oil-format  ${x|html}
