What is sh.js?

sh.js is a JavaScript library for Unix shell scripting working on node.js.

For example, to sort user names in /etc/passwd in a classical shell script, you could write:

cut -f1 -d: /etc/passwd | sort

With sh.js, the following statement would accomplish the same:

sh('cut -f1 -d: /etc/passwd')('sort');

Why try it?

You may find sh.js useful if:

• you use node.js and you want a high-level, prototyping-friendly API to use Unix utilities from JavaScript.
• you would like to try shell scripting in a different language than Bourne's (disclaimer: sh.js is far from ready).

What sh.js isn't

• sh.js isn't an interactive shell (unfortunately, for now). You need to write some JavaScript in a file, and run it with node.js
• sh.js isn't a command interpreter. However, it is a small internal DSL to experiment an alternative to command interpreters such as Bash.

Examples

Run a command:

sh('echo hello');

Change the working directory and run a command in the new directory:

sh.cd('/').and('ls -l');

In a Git repository, put all authors with their email in a file:

sh('git log --pretty=format:"%aN %aE"')
('uniq')('sort').file('AUTHORS');

Report the space availability of the root partition to the remote monitor.lan server:

sh('df')('awk \'{ if ($6 == "/") printf "%s", $5 }\'')
  .result(function(available) {
    sh('curl -d root="' + available + '" https://monitor.lan/disk_report');
  });

For more examples, head to the tutorial.

Limitations

As of now, sh.js still has some serious limitations:

• Node's Streams are not supported. You can't easily redirect standard output to an HTTP stream for instance. This is likely to be resolved but I'm trying to figure out what the right API should be.
• sh.js from an interactive command line is not usable. You can try it, but it'll be a pain. sh.js is better suited to be used in scripts for now. This is not very likely to be worked out any time soon.
• There is a lack of features such as easy file and directory manipulation. This would be a great niche for a library.
• sh.js is not extensible at all for now. It would be nice to have plugins adding high-level APIs abstracting some Unix commands. This seems quite feasible.