Linux signals - Revision history

Leo at 09:03, 24 September 2022

2022-09-24T09:03:02Z

← Older revision		Revision as of 09:03, 24 September 2022
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			Signals are messages that are sent to a program.

			Here are some Linux signals in brief detail. You may quickly list available signals by running <code>kill -l</code>.
	{\| class="wikitable"		{\| class="wikitable"
	!Signal Name		!Signal Name
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	\|SIGINT		\|SIGINT
	\|2		\|2
	\|Signals when the Linux user presses ~~‘CONTROL~~-C’		\|Signals when the Linux user presses <code>Ctrl-c</code>
	\|-		\|-
	\|SIGQUIT		\|SIGQUIT
	\|3		\|3
	\|Signals when the Linux user presses ~~‘CONTROL~~-D’		\|Signals when the Linux user presses <code>Ctrl-d</code>
	\|-		\|-
	\|SIGILL		\|SIGILL
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	\|SIGTRAP		\|SIGTRAP
	\|5		\|5
	\|		\|Trap or breakpoint signal
	\|-		\|-
	\|SIGABRT		\|SIGABRT
	\|6		\|6
	\|		\|Abort signal
	\|-		\|-
	\|SIGBUS		\|SIGBUS
	\|7		\|7
	\|		\|Illegal access to an undefined portion of memory
	\|-		\|-
	\|SIGFPE		\|SIGFPE
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	\|SIGUSR1		\|SIGUSR1
	\|10		\|10
	\|		\|User defined signal. Typically programs will print its status (eg. <code>dd</code>)
	\|-		\|-
	\|SIGSEGV		\|SIGSEGV
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	\|SIGUSR2		\|SIGUSR2
	\|12		\|12
	\|		\|User defined signal.
	\|-		\|-
	\|SIGPIPE		\|SIGPIPE
	\|13		\|13
	\|		\|Write on a pipe with no one to read it
	\|-		\|-
	\|SIGALRM		\|SIGALRM
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	\|SIGSTKFLT		\|SIGSTKFLT
	\|16		\|16
	\|		\|Stack fault
	\|-		\|-
	\|SIGSTOP		\|SIGSTOP
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	\|SIGCONT		\|SIGCONT
	\|18		\|18
	\|		\|Resume program execution from a <code>SIGSTOP</code> or <code>SIGTSTP</code>.
	\|-		\|-
	\|SIGSTOP		\|SIGSTOP
	\|19		\|19
	\|		\|Stop signal sent with <code>kill -STOP</code> to suspend a program. Cannot be ignored by the program.
	\|-		\|-
	\|SIGTSTP		\|SIGTSTP
	\|20		\|20
	\|		\|Signals when the Linux user presses <code>Ctrl-z</code>. May be ignored by the program.
	\|-		\|-
	\|SIGTTIN		\|SIGTTIN
	\|21		\|21
	\|		\|Delivered to a background process if it tries to read from the terminal.
	\|-		\|-
	\|SIGTTOU		\|SIGTTOU
	\|22		\|22
	\|		\|Delivered to a background process if it tries to write to the terminal.
	\|-		\|-
	\|SIGURG		\|SIGURG
	\|23		\|23
	\|		\|Urgent data received on a socket.
	\|-		\|-
	\|SIGXCPU		\|SIGXCPU
	\|24		\|24
	\|		\|Process exceeds CPU limit or time. Save your work before you get killed.
	\|-		\|-
	\|SIGXFSZ		\|SIGXFSZ
	\|25		\|25
	\|		\|File written by this process exceeded some size limit.
	\|-		\|-
	\|SIGVTALRM		\|SIGVTALRM
	\|26		\|26
	\|		\|CPU time elapsed
	\|-		\|-
	\|SIGPROF		\|SIGPROF
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	\|SIGWINCH		\|SIGWINCH
	\|28		\|28
	\|		\|Window size changed.
	\|-		\|-
	\|SIGIO		\|SIGIO
	\|29		\|29
	\|		\|Signal input/output trap. Program should abort unless handled properly.
	\|-		\|-
	\|SIGPWR		\|SIGPWR
	\|30		\|30
	\|		\|Power failure?
	\|-		\|-
	\|SIGSYS		\|SIGSYS
	\|31		\|31
	\|		\|Bad system call
	\|}		\|}

			== See also ==

			* Wikipedia's article outlines all the signals and their default actions: https://en.wikipedia.org/wiki/Signal_(IPC)

Leo at 08:48, 24 September 2022

2022-09-24T08:48:30Z

← Older revision		Revision as of 08:48, 24 September 2022
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	{\| class="wikitable"		{\| class="wikitable"
	\|Signal Name		!Signal Name
	\|Signal Number		!Signal Number
	\|Description		!Description
	\|-		\|-
	\|SIGHUP		\|SIGHUP

Leo: Initial content

2022-09-24T08:48:12Z

Initial content

New page

{| class="wikitable"
|Signal Name
|Signal Number
|Description
|-
|SIGHUP
|1
|Hangs up signals when controlling the terminal or at the end of the controlling processes.
|-
|SIGINT
|2
|Signals when the Linux user presses ‘CONTROL-C’
|-
|SIGQUIT
|3
|Signals when the Linux user presses ‘CONTROL-D’
|-
|SIGILL
|4
|Illegal instruction trap
|-
|SIGTRAP
|5
|
|-
|SIGABRT
|6
|
|-
|SIGBUS
|7
|
|-
|SIGFPE
|8
|Signals when any unexpected mathematical operation is performed.
|-
|SIGKILL
|9
|When any of the process issues this signal, it will quit immediately.
|-
|SIGUSR1
|10
|
|-
|SIGSEGV
|11
|Segmentation fault
|-
|SIGUSR2
|12
|
|-
|SIGPIPE
|13
|
|-
|SIGALRM
|14
|Signals for alarm clock
|-
|SIGTERM
|15
|Signals to terminate the process or the software.
|-
|SIGSTKFLT
|16
|
|-
|SIGSTOP
|17
|Signals to stop the process in Linux.
|-
|SIGCONT
|18
|
|-
|SIGSTOP
|19
|
|-
|SIGTSTP
|20
|
|-
|SIGTTIN
|21
|
|-
|SIGTTOU
|22
|
|-
|SIGURG
|23
|
|-
|SIGXCPU
|24
|
|-
|SIGXFSZ
|25
|
|-
|SIGVTALRM
|26
|
|-
|SIGPROF
|27
|
|-
|SIGWINCH
|28
|
|-
|SIGIO
|29
|
|-
|SIGPWR
|30
|
|-
|SIGSYS
|31
|
|}