Usage: tilt <options> <file>
Process template <file> and write output to stdout. With no <file> or
when <file> is '-', read template from stdin and use the --type option
to determine the template's type.

Options
  -l, --list                List template engines + file patterns and exit
  -t, --type=<pattern>      Use this template engine; required if no <file>
  -y, --layout=<file>       Use <file> as a layout template

  -D<name>=<value>          Define variable <name> as <value>
  -d, --define-file=<file>  Load YAML from <file> and use for variables
  --vars=<ruby>             Evaluate <ruby> to Hash and use for variables

  -h, --help                Show this help message

Convert markdown to HTML:
  $ tilt foo.markdown > foo.html

Process ERB template:
  $ echo "Answer: <%= 2 + 2 %>" | tilt -t erb
  Answer: 4

Define variables:
  $ echo "Answer: <%= 2 + n %>" | tilt -t erb --vars="{:n=>40}"
  Answer: 42
  $ echo "Answer: <%= 2 + n.to_i %>" | tilt -t erb -Dn=40
  Answer: 42