def usage(myname='xia2ccp4i.py'):
    """return a usage string"""
    msg = """%s [options]

Options:
-h, --help               show this help message and exit
-p FOO, --project=FOO    override the project name taken from xia2, and call
                         the CCP4 project FOO
-x BAR, --xia2dir=BAR    specify the location of the top-level xia2 processing
                         directory (omission implies BAR=".")

Extract project name and data from a xia2 processing run, create a standalone
ccp4i project and start ccp4i with that project.

Please note that this standalone ccp4i project will not be in the global
projects database of ccp4i. However it may be added later using the
'Directories&ProjectDir' button in ccp4i. The list of jobs performed in the
standalone project will remain intact after the import.
"""
    return msg % myname
