covstat is an R package (with Perl wrapper script) for computing P-values that stand for a bias in compensatory base changes spanning two nucleotide multiple sequence alignments.

Installation:
It is assumed that R is installed.

R CMD INSTALL covstat_0.5.2.tar.gz

The recommended Perl wrapper script is located in the inst/bin/ directory. This can be obtained as follows:
tar xvfz covstat_0.5.2.tar.gz
cd covstat_0.5.2/inst/bin
The executable Perl script is called covstat. Issuing ./covstat provides further help information.

