Urchin

A Unix shell for Ruby programmers.

If you have any ideas for what you think this should mean, please submit a ticket!

Urchin does not aim to be POSIX compliant, but is heavily influenced by Bash and Zsh. Urchin aims to make Ruby a first class citizen in the shell and be a good place for experimenting with new shell ideas.

Authors

Mark Somerville mark@scottishclimbs.com http://mark.scottishclimbs.com/ @_Spakman Spakman on Freenode

Current status

Preparing to release version 0.2.0. On Linux this will be beta quality. It is considerably less tested on other platforms. I have been using it as my login shell since version 0.1.0 and it has been pretty stable.

Quite a lot of common Unix shell stuff is implemented: job control, redirections, tilde expansion, aliasing, globbing and environment variables. Functions are the most obvious thing missing from that list. These will most likely appear in 0.3.0.

Straightforward inline Ruby is available! This was the original inspiration for the project (although the vision has grown somewhat now). This allows writing Ruby processes directly on the command line, without the need to escape special characters. This will likely be expanded and improved upon in later releases.

I will create a gem for version 0.2.0.

Current problems

GitHub is used for ticket tracking: https://github.com/Spakman/urchin/issues

Requirements

Ruby

Tested with MRI 1.8.7, 1.9.2 and 1.9.3-dev on Linux.

If running using 1.9.2 on a laptop, be aware of bug #3436 (http://redmine.ruby-lang.org/issues/show/3436). This should be fixed when 1.9.3 is released.

rb-readline

Since version 0.2.0, Urchin relies on rb-readline. Use the latest version or check it out from GitHub[1]. I'm one of the maintainers for rb-readline and always check that Urchin works with the latest version.

1 - https://github.com/luislavena/rb-readline

ruby-termios

Tested with version 0.9.6.

Some examples that work

Pipelines:

ls -la | head -n2

Calling a new Ruby process (~@ is the default delimiter):

ls --no-color |~@ puts STDIN.read.reverse ~@ | sort
ls --no-color |~@ o s.reverse ~@ | sort

Redirecting STDOUT, STDIN, STDERR:

uptime > output
uptime >> output
ruby -e 'puts STDIN.read; STDERR.puts 33' < input > out_and_err 2>&1

Backgrounding jobs:

sleep 60 &

Multiple jobs:

sleep 60 & man sleep

sleep 60; echo "it's over"

Quoted and unquoted parameters:

grep -r '"hello"' .
grep -r "\"hello\"" .
ls my\ annoyingly\ named\ dir
find . -name 'hello' -exec chmod 660 {} \;

Globbing:

ls **/*.rb
mv image?.{png,gif} images

Tilde expansion:

ls ~/src/
ls ~mark

Reading and setting environment variables:

echo $PATH
echo abx${HOME}xyz
export HELLO="Yo man!"

Simple arithmetic (lines starting with a digit are eval-ed as Ruby):

17 * 123

Command expansion:

ps `pgrep urchin`

Job control (uses fg, bg and jobs builtins).

Spakman / urchin

readme