pid is the process identification number
of the server. They are located in the directory specified by the
TMPDIR environment variable (Appendix C, All environment variables which affect CVS), the -T global
option (the section called “Global options”), or failing that
In most cases the server will remove the temporary directory when it is done, whether it finishes normally or abnormally. However, there are a few cases in which the server does not or cannot remove the temporary directory, for example:
If the server aborts due to an internal server error, it may preserve the directory to aid in debugging
If the server is killed in a way that it has no way of cleaning up (most notably, kill -KILL on unix).
If the system shuts down without an orderly shutdown, which tells the server to clean up.
In cases such as this, you will need to manually remove the
pid directories. As long
as there is no server running with process identification number
pid, it is safe to do so.