Generic

ID #1120

Why are kill signal names not working (f.i. kill -HUP)?

The FREESCO kill command is a stripped down version of the kill command (all to safe space on the floppy). This means the kill signal names are not supported. However with the numeric value of the kill signal the kill command works.

A list of kill signal numbers with their names can be found here

List of common kill signals

Name Numeric Description
SIGHUP
1
Hang up. If the terminal becomes disconnected from a process, this signal is sent automatically to the process. Sending a process this signal often causes it to reread its configuration files, so it is useful instead of restarting the process. Always check the man page to see if a process has this behavior.
SIGINT
2
Interrupt from keyboard. Issued if you press ^C.
SIGQUIT
3
Quit from keyboard. Issued if you press ^D.
SIGFPE
8
Floating point exception. Issued automatically to a program performing some kind of illegal mathematical operation.
SIGKILL
9
Kill signal. This is one of the signals that can never be caught by a process. If a process gets this signal it must quit immediately and will not perform any clean-up operations (like closing files or removing temporary files). You can send a process a SIGKILL signal if there is no other means of destroying it.
SIGUSR1
10
User signals. These signals are available to developers when they need extra functionality. For example, some processes begin logging debug messages when you send them SIGUSR1.
SIGUSR2
12
SIGSEGV
11
Segmentation violation. Issued automatically when a process tries to access memory outside of its allowable address space, equivalent to a Fatal Exception or General Protection Fault under Windows. Note that programs with bugs or programs in the process of being developed often get these signals. A program receiving a SIGSEGV, however, can never cause the rest of the system to be compromised. If the kernel itself were to receive such an error, it would cause the system to come down, but such is extremely rare.
SIGPIPE
13
Pipe died. A program was writing to a pipe, the other end of which is no longer available.
SIGTERM
15
Terminate. Cause the program to quit gracefully.
SIGCHLD
17
Child terminate. Sent to a parent process every time one of its spawned processes dies.

f.i. If you see somewhere a process reacts to the SIGUSR1 signal, then the command on FREESCO would be:

kill -10 pid

where pid is the process ID as listed in the output of the 'ps' command.

Last update: 2004-12-01 15:29
Author: dingetje
Revision: 1.0

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