README.markdown @ 6399abfdb127

peat
====

`peat` repeats commands.

It's kind of like [Kicker][] except:

* It doesn't use inotify or OS X FSEvents, so it'll run anywhere.
* It doesn't require external libraries, so it'll run anywhere with Python.
* It won't eat your CPU (unless you try to watch too much).
* It takes paths to watch on standard input so you can use something like
  find(1) or [friendly-find][] to specify what to watch.

[Kicker]: https://github.com/alloy/kicker
[friendly-find]: https://github.com/sjl/friendly-find

Installation
------------

Get the `peat` script on your machine and into your `$PATH` somehow.  Copy and
paste it, `curl` it, or clone the repository.  Make sure it's executable.
That's it.

Usage
-----

Generate a list of files you want to watch for changes, separated by whitespace.
echo(1), find(1) or [friendly-find][] are good for this:

    $ ffind '.*.py$'
    ./foo.py
    ./bar.py

    $ echo *.py
    foo.py bar.py

Now pipe that to `peat`, and specify the command you want to run whenever one of
those files changes:

    $ ffind '.*.py$' | peat 'echo "A file changed!"'

Use `Ctrl-C` to stop.

The command to run needs to be specified as a single argument to `peat`.  You
can do this with a shell string as seen above.  Using a single-quoted string
like this will preserve wildcards and such:

    $ ffind '.*.py$' | peat 'rm *.pyc'

This will delete all `.pyc` files in the current directory when a Python file is
modified.  Google around for "shell quoting" if you don't understand what's
happening here.

### Dynamic File Listing

If you want to build the file list fresh each time (so that `peat` will pick up
newly created files without having to restart it) you can use the `--dynamic`
option.

Instead of piping in the list of files to watch, you'll pipe in a *command* that
`peat` will run to generate the list before every check.  For example:

    $ ffind ".markdown$"
    ./foo.markdown
    ./bar/baz.markdown

    $ echo 'ffind ".markdown$"'
    ffind ".markdown$"

    $ echo 'ffind ".markdown$"' | peat --dynamic 'echo "A file changed!"'

If your command contains quotes you'll need to make sure they get passed
into peat properly.  For example, the following will **not** work:

    $ echo "find . -name '*.markdown'" | peat --dynamic ...

The problem is that the shell will expand the `*` in the double-quoted string
before it ever gets to `peat`.  Google around and learn about shell quoting if
you don't understand.  This can be tricky.  You've been warned.

### Full Usage

Here's the full usage:

    Usage: peat [options] COMMAND

    COMMAND should be given as a single argument using a shell string.

    A list of paths to watch should be piped in on standard input.

    For example:

        find . | peat './test.sh'
        find . -name '*.py' | peat 'rm *.pyc'
        find . -name '*.py' -print0 | peat -0 'rm *.pyc'

    If --dynamic is given, a command to generate the list should be piped in
    on standard input instead.  It will be used to generate the list of files
    to check before each run.

    This command must be quoted properly, and this can be tricky.  Make sure
    you know what you're doing.

    For example:

        echo find . | peat --dynamic './test.sh'
        echo find . -name '*.py' | peat --dynamic 'rm *.pyc'


    Options:
      -h, --help            show this help message and exit
      -i N, --interval=N    interval between checks in milliseconds
      -I, --smart-interval  determine the interval based on number of files
                            watched (default)
      -d, --dynamic         take a command on standard input to generate the list
                            of files to watch
      -D, --no-dynamic      take a list of files to watch on standard in (default)
      -c, --clear           clear screen before runs (default)
      -C, --no-clear        don't clear screen before runs
      -v, --verbose         show extra logging output (default)
      -q, --quiet           don't show extra logging output
      -w, --whitespace      assume paths on stdin are separated by whitespace
                            (default)
      -n, --newlines        assume paths on stdin are separated by newlines
      -s, --spaces          assume paths on stdin are separated by spaces
      -0, --zero            assume paths on stdin are separated by null bytes

License
-------

Copyright 2012 Steve Losh and contributors.

Licensed under [version 3 of the GPL][gpl].

Remember that you can use GPL'ed software through their command line interfaces
without any license-related restrictions.  `peat`'s command line interface is
the only stable one, so it's the only one you should ever be using anyway.  The
license doesn't affect you unless you're:

* Trying to copy the code and release a non-GPL'ed version of `peat`.
* Trying to use it as a Python module from other Python code (for your own
  sanity I urge you to not do this) and release the result under a non-GPL
  license.

[gpl]: http://www.gnu.org/copyleft/gpl.html