How do I send a signal to another process?

How do I send a signal to another process? Sending a Signal to Another Process: System Call kill() System call kill() takes two arguments. The first, pid, is the process ID you want to send a signal to, and the second, sig, is the signal you want to send. Therefore, you have to find some way to know the process ID of the other party.

What command do you use to send a signal to a process? You can send various signals to commands / process and shell scripts using the, pkill command, kill command, and killall command.

How do you send a signal to a kill? 

The kill command in UNIX enables the user to send a signal to a process.

Sending Kill Signals to a Process.

Signal No.Signal NameMeaning
2INTInterrupt (same as pressing Control+C in a terminal session)

How do I submit a SIGUSR2 to a process? 

To send the ttsession process a SIGUSR2:
  1. Enter the ps command to find the process identifier (pid) of the ttsession process. % ps -ef | grep ttsession.
  2. Enter the kill command to send a SIGUSR2 signal to ttsession . % kill -USR2 ttsession_pid.

How do I send a signal to another process? – Additional Questions

What signal is Ctrl D?

Ctrl + D ( ^D ) means end of file. It only works at the beginning of a line (I’m simplifying a little), and has no effect if the program isn’t reading input from the terminal.

How do you use SIGUSR1 and SIGUSR2?

What is SIGUSR1 used for?

The SIGUSR1 and SIGUSR2 signals are set aside for you to use any way you want. They’re useful for simple interprocess communication, if you write a signal handler for them in the program that receives the signal. There is an example showing the use of SIGUSR1 and SIGUSR2 in Signaling Another Process.

What is Sigquit on Linux?

The SIGTERM and SIGQUIT signals are meant to terminate the process. In this case, we are specifically requesting to finish it. SIGTERM is the default signal when we use the kill command. The default action of both signals is to terminate the process. However, SIGQUIT also generates a core dump before exiting.

What is Sigaction in C?

The sigaction() function allows the calling process to examine and/or specify the action to be associated with a specific signal.

What does SIGTERM mean?

The SIGTERM signal is a generic signal used to cause program termination. Unlike SIGKILL , this signal can be blocked, handled, and ignored. It is the normal way to politely ask a program to terminate. The shell command kill generates SIGTERM by default.


The CTRL + C is one signal in C or C++. So we can catch by signal catching technique. For this signal, the code is SIGINT (Signal for Interrupt).

What is the difference between SIGTERM and SIGKILL?

SIGTERM gracefully kills the process whereas SIGKILL kills the process immediately. SIGTERM signal can be handled, ignored, and blocked, but SIGKILL cannot be handled or blocked. SIGTERM doesn’t kill the child processes. SIGKILL kills the child processes as well.

What does signal No 15 means in Linux?

(signal 15) is a request to the program to terminate. If the program has a signal handler for SIGTERM that does not actually terminate the application, this kill may have no effect. This is the default signal sent by kill. SIGKILL.

What is signal 8 Linux?

Signal typically alert a process to some event, such as a segmentation fault, or the user pressing Ctrl-C. Linux kernel implements about 30 signals.

Linux Processes and Signals.

SIGTRAP5Trace trap (POSIX)
SIGBUS7BUS error (4.2 BSD)
SIGFPE8Floating point exception (ANSI)

What number is SIGUSR1?


What is the name of signal 19?


What is a signal 29?

Police code 29 means Death.

Can SIGTERM be caught?

The SIGKILL or SIGSTOP signals cannot be caught or ignored. You can catch a signal in Linux by using sigaction . Use only functions that are async-signal-safe in the signal handler.

Can Sigcont be caught?

SIGTHSTOP and SIGTHCONT cannot be caught or ignored; they always take effect.

What signals Cannot be caught?

There are two signals which cannot be intercepted and handled: SIGKILL and SIGSTOP.

Can SIGCONT be ignored?

You can ignore SIGCONT , but it always causes the process to be continued anyway if it is stopped. Sending a SIGCONT signal to a process causes any pending stop signals for that process to be discarded. Likewise, any pending SIGCONT signals for a process are discarded when it receives a stop signal.

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