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Build Status

Oil is a new Unix shell. Why Create a New Unix Shell?

This repo contains a bash-compatible shell called OSH, written in Python.

The dialect of bash that is recognized is called the OSH language. The Oil language has been designed but not implemented.

OSH is written in Python, but we deploy a native executable. A subset of the Python-2.7.13/ directory is packaged with the application.

Quick Start for Developers on Linux

Clone the repo, build the Python extension, and run bin/osh.

bash$ build/ minimal
# Now you should have a symlink in the repository root directory

bash$ bin/osh
osh$ name=world
osh$ echo "hello $name"
hello world

Most shell scripts should run, e.g. with osh

You can also download the latest release and build it, which is linked from the home page. (This is the only way to try OSH on OS X. Developer builds don't work on OS X.)


For information on how to build and test Oil, see Contributing on the wiki.

If you'd like to contribute, please post a message on the #oil-dev channel of Let us know what you're thinking, or let us know if you're having problems getting started.

The blog has updates on the project status.

Code Overview

Try this to show a summary of what's in the repo and their line counts:

$ metrics/ all

(Other functions in this file may be useful as well.)

Directory Structure

# Development Scripts

benchmarks/       # Benchmarks should be run on multiple machines.
metrics/          # Metrics don't change between machines (e.g. code size)
build/            # Build automation
  oil-defs/       # Files that define our slice of CPython.          # For development builds, running CPython
devtools/         # For Oil developers (not end users)      # Documents the release process.
misc/             # Other development scripts
demo/             # Demonstrations of bash/shell features.  Could be
                  # moved to tests/ if automated.
web/              # HTML/JS/CSS for tests and tools

# Tests

test/             # Test automation         ## Types of test runner: unit, spec, wild, smoke      # shell spec test framework
gold/             # Gold Test cases.
spec/             # spec test cases
  bin/            # tools used in many spec tests
  testdata/       # scripts for specific test cases
  errors/         # TODO: migrate these bad shell scripts
types/            # Scripts for running MyPy and PyAnnotate, etc.

# DSLs / Code Generators

asdl/             # ASDL implementation, derived from CPython
pgen2/            # Parser Generator, borrowed from CPython
mycpp/            # Experimental translator from typed Python to C++.
                  # Depends on MyPy.
opy/              # Python compiler in Python
  lib/            # Common code
  compiler2/      # Bytecode compiler
  byterun/        # Metacircular bytecode VM in Python
  gold/           # tests
  byterun/        # Unused bytecode interpreter

# Oil Code

Python-2.7.13/    # CPython is the initial basis for the Oil VM
bin/              # Programs to run (bin/osh)
core/             # Most of the Oil and OSH implementation.
native/           # Native code for Oil, e.g. libc.c
frontend/         # Lexing/Parsing code common to Oil and OSH.
oil_lang/         # Oil parser and evaluator.
osh/              # OSH parser and evaluator.
pylib/            # Borrowed from the Python standard library.
tools/            # User-facing tools, e.g. the osh2oil translator

# Temporary Directories

_bin/             # Native executables are put here
_build/           # Temporary build files
_devbuild/        # Developer build files not deleted upon 'make clean'
  gen/            # Generated Python and C code
_deps/            # build dependencies like re2c
_tmp/             # Test suites and other temp files
_release/         # Source release tarballs are put here
  VERSION/        # Published at$VERSION/
    web/          # Static files, copy of $REPO_ROOT/web

# Docs
doc/              # A mix of docs         # For Oil developers

LICENSE.txt       # For end users

# End user build system


Unit tests are named and live next to

More info

Right now we're using /r/oilshell on Reddit for general discussion.

I have docs that need to be cleaned up and published. For now, there is a fair amount of design information on the blog at

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