Syntax
======

A syntax of shellflow is very similar to bash script. Most important
difference is annotating input files and output files with parentheses
and brackets.

Input files
-----------

All input files should be enclosed with parentheses.

.. code:: bash

    cat ((INPUT_FILE))

If some input files are not appeared in command line, it should be
written in comment.

.. code:: bash

    gcc ((hello.c)) # ((hello.h))   this command depends on hello.c and hello.h

When glob is used, all input files should be exists in advanced of
shellflow runing.

Output files
------------

All output files should be enclosed with brackets.

.. code:: bash

    date >> [[OUTPUT]]

Varaible
--------

A varaible should be enclosed with curly brackets, when the variable is
used in command line.

.. code:: bash

    echo {{variable}}

To set value to variable, flowscript, embedded script language in
shellflow, or parameter file should be used. When a line starts with
``#%``, the line will be parsed as flowscript.

.. code:: bash

    #% varaible = "foo"

Loop
----

``for`` loop is supported in shellflow. ``do`` and ``done`` are required
in shellflow.

.. code:: bash

    for x in a b c; do
        echo {{x}} > {{x}}
    done

Variable names should be enclosed with curly brackets.

When glob is used, all input files should be exists in advanced of
shellflow runing.

if
--

``if`` statement is not supported currently.