The installation consists of code, catalog, and stellar atmosphere data. The IDL procedure code can be downloaded from http://www.eso.org/chummel/oyster/download.html. The external C and FORTRAN library compiled for Linux 64-bit systems is included, but can be recompiled if necessary from the C code which can be obtained from the author.
Download files oyster.tar.gz, catalogs.tar.gz and atmospheres.tar.gz and unpack first (e.g. tar zxf oyster.tar.gz). Then unpack the other two inside the newly created oyster home folder. Two directories are created, atmospheres and catalogs.