# Using configuration files

The configuration files provide extra information to customize the execution of a command. Unlike the command-line options, they can be prepared once and reused repeatedly. By means of them, the number of command-line arguments can be significantly reduced.

The configuration file consists of a set of parameters stored in a text file. Each parameter is stored on a separate line in the following form: <replaceable>name</replaceable> = <replaceable>value</replaceable>, all other lines are silently ignored. Parameter names are always case-sensitive. A hash character starts a comment string, all following content is ignored up to the end of the present line.

The `-p` option must be used to instruct the program to read and process the configuration file. Whenever there is a conflict between a configuration file parameter and an option of the same meaning, the option always take precedence.

Example of configuration file:

    # Sample configuration file
    right-ascension = `23.0253`        # GSC 2750 854
    declination     = `30.7408`
    longitude       = `16.6667`        # Brno
    latitude        = `49.2167`