Processes
- 1. Processes
- 2. • A process is created every time you issue a command. It is an instance of a running program. • Question: What is an instance? (Think programming) • A running process may spawn child processes • e.g., a man process may invoke your default pager, thereby spawning a more process. • The command ps will let you see all of your running processes. Some useful options include: • -e – lets you see information about all running processes, even those that are not yours. • -f – displays more detailed information Processes
- 3. • A interactive process launched by the shell that is not a daemon is called a job. • Child processes would not be jobs • Question: What is a daemon? • To see your running jobs, issue the jobs command. Jobs
- 4. • There are two was to run processes/jobs in the background: 1. Start the job as you normally would. Suspend the job. Tell the system to run the suspended job in the background; e.g., • man sort • CTRL^Z • Bg 2. Start the job in the background using the ampersand: • man sort & • Question: Which of these is a command line command and why? Running processes/jobs in the background
- 5. • To foreground your most recently suspended or backgrounded job, type fg • To foreground another job: • Determine its job number, via the jobs command • Suppose you were interested in foregrounding job number 3. You would then issue the command: fg %3 Foregrounding a job
- 6. • To kill a process: kill –SIGKILL processID or kill –s 9 processID • To kill a job: kill –SIGKILL %job-number **Note the percent symbol!** • To kill all processes by name rather than process ID: kill –SIGKILL name For example: kill –SIGKILL man will all instances of the man command as well as any child processes Killing jobs and processes