echo 'docker run -v /your/local/path:/rsyslog-doc <container-name> command
where command is one of:
build-doc    - generate documentation (currently HTML only)
help         - display this help message
bash         - start an interactive shell (<CTL>-d terminates)
version-info - outputs some information of component used in container
git-clone    - clone the official rsyslog-doc project into /rsyslog mount
               this is a quick way to populate /rsyslog, which must be empty before

Environment variables (set with -eVAR=val on docker run):
FORMAT       - html (default) or another builder format
STRICT       - options to cause strict sphinx mode (default "-n -W")
DEBUG        - set to "on" to turn on some minimal container debugging
SPHINX_EXTRA_OPTS - provides any option to sphinx the user wishes, e.g. -q for quiet builds

bind mounts (mount with -v/local/path:/container on docker run):
/output      - output files will be placed here. If not mounted, output will be under
               /rsyslog-doc/output
/rsyslog-doc - checked-out rsyslog doc project; if not mounted but /output is, an
               automatic git clone is done to a temporary volume

An alternate way to specify extra options is by adding them, one per line, to the
SPHINX_EXTRA_OPTS file. The name must be exactly as given, and it must be stored in
the doc project home directory. This method is especially useful for complex options
which otherwise might be hard to escape so that the shell does not misinterpret them.
If both the file SPHINX_EXTRA_OPTS and the environment variable SPHINX_EXTRA_OPTS are
given, both are used.
'
