OSH versus Oil

Here is a short guide:

• bin/osh runs the OSH language, which is extremely compatible with POSIX shell and bash. It's designed to run existing scripts.
• bin/oil runs the Oil language, a new shell language that's designed to be familiar to Python and JavaScript users. You can gracefully upgrade your shell scripts to it, or write brand new scripts in it.
  • See A Tour of the Oil Language

But they actually run in the same binary and use the same parser and interpreter! bin/osh and bin/oil are symlinks (or one line "forwarding" scripts).

There are many global shell options like shopt --set parse_brace that change OSH into Oil. Running bin/oil is equivalent to running bin/osh with the option group shopt --set oil:all. See the full option list below.

(As of 11/2021, OSH is a lot more mature than Oil.)

Examples

For examples of the syntax, see The Simplest Explanation of Oil.

More Detail

• https://github.com/NixOS/rfcs/pull/99#issuecomment-962495958
  • Four Features That Justify a New Unix Shell (OSH)
  • Five Essential Features of the Oil Language (Oil, not done yet)

Full Option List in oil:all

This command lets you see the difference between OSH and Oil in detail! -s means that the option is set when running in Oil mode, and -u means that it's unset.

$ oil -c 'shopt -p oil:all'
shopt -s command_sub_errexit
shopt -u dashglob
shopt -s errexit
shopt -u expand_aliases
shopt -s inherit_errexit
shopt -s nounset
shopt -s nullglob
shopt -s parse_amp
shopt -s parse_at
shopt -s parse_at_all
shopt -u parse_backslash
shopt -u parse_backticks
shopt -s parse_brace
shopt -u parse_dollar
shopt -s parse_equals
shopt -u parse_ignored
shopt -s parse_paren
shopt -s parse_raw_string
shopt -s parse_triple_quote
shopt -s pipefail
shopt -s process_sub_fail
shopt -u redefine_proc
shopt -s sigpipe_status_ok
shopt -s simple_echo
shopt -s simple_eval_builtin
shopt -s simple_test_builtin
shopt -s simple_word_eval
shopt -s strict_argv
shopt -s strict_arith
shopt -s strict_array
shopt -s strict_control_flow
shopt -s strict_errexit
shopt -s strict_glob
shopt -s strict_nameref
shopt -s strict_tilde
shopt -s strict_word_eval
shopt -u xtrace_details
shopt -s xtrace_rich