cancel [ request-id ... ] printer ...
Specifying a request-id cancels the associated request even if it is currently printing. Specifying a printer cancels the request that is currently printing on that printer. In either case, the cancellation of a request that is currently printing frees the printer to print its next available request.
cancel allows only the root user and printer administrators cancel any job. Other users may only cancel their own jobs. If a job is cancelled by root or a printer administrator, the person who initiated the job is informed by mail unless the file /etc/default/lpd contains CANCEL_MAIL=NO.
ISO/IEC DIS 99452:1992, Information technology
Portable Operating System Interface (POSIX)
Part 2: Shell and Utilities (IEEE Std 1003.2
1992);
AT&T SVID Issue 2;
X/Open CAE Specification, Commands and Utilities, Issue 4, 1992.