Installation Instructions for Package rBLAST

1. Install BLAST+
    The BLAST+ software needs to be installed on your system. The official
    installation instructions for different plattforms are available at
    https://www.ncbi.nlm.nih.gov/books/NBK569861/

    Windows
    -------
    Follow the instructions at https://www.ncbi.nlm.nih.gov/books/NBK52637/

    Linux/Unix
    ----------
    Precombiled software package are already available for many Linux
    distributions. The package is typically called ⁠ncbi-blast+. For example
    on Debian/Ubuntu, the package can be installed using the APT
    package manager:
    apt-get install ncbi-blast+

    MacOSX
    ------
    The easiest approach is to use the .dmg installer file from
    https://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/LATEST/


2. Checking that the path environment variables are correctly set
    R needs to be able to find the executable. The installers for LINUX/Unix
    and MacOSX set the correct values, so this is is mostly only an issue
    with Windows. After installing the software, try in R
    > Sys.which("blastn")

    If the command returns "" instead of
    the path to the executable, then you need to set the environment variable
    called PATH. In R
    Sys.setenv(PATH = paste(Sys.getenv("PATH"),
        "path_to_your_BLAST_installation", sep=.Platform$path.sep))

    More details about setting the environment variables permanently can be
    found in the Windows installation guide at
    https://www.ncbi.nlm.nih.gov/books/NBK52637/