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Unix Advanced: Difference between revisions
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→Killing Processes
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cokane 68730 0.0 0.3 1620 1324 pi T 5:36PM 0:00.02 slrn | cokane 68730 0.0 0.3 1620 1324 pi T 5:36PM 0:00.02 slrn | ||
cokane 68741 0.0 0.0 388 220 pi R+ 5:36PM 0:00.00 ps -u | cokane 68741 0.0 0.0 388 220 pi R+ 5:36PM 0:00.00 ps -u | ||
prompt$ ps | prompt$ ps | ||
PID TT STAT TIME COMMAND | PID TT STAT TIME COMMAND | ||
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You see in the above example that when a process gets killed (or finishes itself), the shell will print that the process has finished or has been killed. In the above example you can see that it shows the job number in square brackets, then the reason the process returned (that it was killed) and the name of the process. | You see in the above example that when a process gets killed (or finishes itself), the shell will print that the process has finished or has been killed. In the above example you can see that it shows the job number in square brackets, then the reason the process returned (that it was killed) and the name of the process. | ||
Signals | |||
== Signals == | |||
Now I will (attempt to) explain signals in UNIX... | Now I will (attempt to) explain signals in UNIX... | ||
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Below I will list some of the most common signals and what they're used for. I reserve the right to be very wrong about some of them :o) | Below I will list some of the most common signals and what they're used for. I reserve the right to be very wrong about some of them :o) | ||
*SIGKILL As explained already... to kill a process | *SIGKILL | ||
As explained already... to kill a process | |||
*SIGTERM Similar to SIGKILL but it won't kill the process straight away. | *SIGTERM | ||
Similar to SIGKILL but it won't kill the process straight away. | |||
*SIGSTOP This is the signal which suspends a process.. | *SIGSTOP | ||
This is the signal which suspends a process.. | |||
*SIGSTP Similar to SIGSTOP, this is the signal that pressing | *SIGSTP | ||
Similar to SIGSTOP, this is the signal that pressing CTRL + Z sends. | |||
*SIGCONT The signal sent to continue a suspended process. | *SIGCONT | ||
The signal sent to continue a suspended process. | |||
*SIGTTOU This occurs when a process running in the background attempts | *SIGTTOU | ||
This occurs when a process running in the background attempts to write to the terminal. The process gets suspended. | |||
*SIGTTIN As above except occurs when process tries to read input | *SIGTTIN | ||
As above except occurs when process tries to read input from terminal. | |||
*SIGHUP The "hang up" signal, nowadays sending this to a process | *SIGHUP | ||
The "hang up" signal, nowadays sending this to a process will cause the process (if it's a daemon) to re-read its configuration files without you having to restart the process itself. | |||
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Hopefully you've found this tutorial a bit helpful and have maybe learnt something as well from it as well. | Hopefully you've found this tutorial a bit helpful and have maybe learnt something as well from it as well. | ||
== Links == | |||