# [bash] export -n ENSEMBL_CVS_ROOT_DIR # will stop exporting, but the value in current shell stays as it was
# [tcsh] unsetenv ENSEMBL_CVS_ROOT_DIR # will destroy the variable even in current shell, and stop exporting
'ensembl_cvs_root_dir'=>$self->o('ensembl_root_dir')||$self->o('ensembl_cvs_root_dir')||$ENV{'ENSEMBL_ROOT_DIR'}||$ENV{'ENSEMBL_CVS_ROOT_DIR'},# it will make sense to set this variable if you are going to use ehive with ensembl
# have to be careful not to check for $self->o('ensembl_cvs_root_dir') unless no env variable is set, or else
# it will cause options missing errors. Also, the $self->o() system doesn't support optional options at
# the time of this commit, so we can only have one of ensembl_root_dir or ensembl_cvs_root_dir, otherwise
# there would always be an options missing error. We choose ensembl_cvs_root_dir for backwards compatibility.