The lpq program is the main method used to monitor queues. You can obtain the available options by using:
h4: {306} % lpq -=
lpq: Illegal option '='
usage: lpq [-aAclV] [-Ddebuglevel] [-Pprinter] [-tsleeptime]
-a - all printers
-c - clear screen before update
-l - increase (lengthen) detailed status information
additional l flags add more detail.
-L - maximum detailed status information
-n linecount - linecount lines of detailed status information
-Ddebuglevel - debug level
-Pprinter - specify printer
-s - short (summary) format
-tsleeptime - sleeptime between updates
-V - print version information
If no queue is specified, then the default queue is used, with -Pprinter@host causing a direct connection to the named host. The -a literal selects all queues.