# Text Options of the Executable phc

Text options of `phc` do not compute anything, but provide text information about `phc`.

While the regular options of `phc` start with a single dash `-`, the text options are double dashed, they start with `--`.

## phc --version : displays the current version string

Typing at the command prompt `phc --version` displays the version string which includes the current version number and the release date.

## phc --license : writes the license to screen

The output of

    phc --license

is

    PHCpack is free and open source software.
    You can redistribute the code and/or modify it under
    the GNU General Pulic License as published by
    the Free Software Foundation.

## phc --cite : how to cite PHCpack

Typing `phc --cite` at the command prompt displays

    To cite PHCpack in publications use:

    Jan Verschelde:
    Algorithm 795: PHCpack: A general-purpose solver for polynomial
    systems by homotopy continuation.
    ACM Transactions on Mathematical Software, 25(2):251--276, 1999.

## phc --help : writes helpful information to screen

Typing at the command prompt `phc --help` provides some help to get started with the quickest use, that is: with the blackbox solver.

To obtain help about the blackbox solver, type `phc -b --help` or `phc --help -b` where the `--help` may be abbreviated by `-h`.