The help information (usage information) does not match the usage
information in the man page:
# at -h
Usage: at [-V] [-q x] [-f file] [-m] time
atq [-V] [-q x]
atrm [-V] [-q x] job ...
batch [-V] [-f file] [-m]
at [-V] [-q queue] [-f file] [-mldbv] TIME
at -c job [job...]
atq [-V] [-q queue]
atrm [-V] job [job...]
batch [-V] [-q queue] [-f file] [-mv] [TIME]
The second line (at -c job [job...]) is missing from the usage shown
fixed in at-3.1.8-57.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.