Two-Minute Drill

Viewing Processes

q	The ps command without any option and argument only displays the information about those processes whose effective UID and the terminal is the same as the user who issued the command.
q	The pgrep command can be used to display information only about selective processes.
q	You should use the prstat command to display the process information if you want the output refreshed periodically.

Controlling Processes

q	You can control a process by using the pgrep command to get its process ID, and then using a control command such as pstop, and prun.
q	You can also control a process by sending it a signal with the kill command.
q	Instead of using pgrep and kill, you can just use pkill, which finds the process and sends it the signal.

Scheduling Processes

q	You schedule a process for repeated execution by entering a command in a crontab file, and you schedule a process for one-time execution in the future by issuing the at command.
q	If the cron.allow file exists, only the users listed in this file can create, edit, display, or remove crontab files.
q	If the cron.allow file does not exist, all users except those listed in the cron.deny file can submit the crontab files.
q	If neither cron.allow nor cron.deny exists, only a superuser can execute the crontab command.

Managing Printers

q	The lpstat command displays the status of the LP print service.
q	The print scheduler, lpsched, is started with the /usr/lib/lpsched command and stopped with the lpsut command.
q	You can use the cancel command to cancel a print request.
q	You can use the lpadmin command to configure the LP print service. Do not edit the configuration files manually.