kill: command not found

Different commands are used to send signals to processes to terminate or “kill” them. This is necessary when a process becomes unresponsive (hangs), causes system instability, or fails to relinquish control over a file you’re trying to modify.

The “kill” command sends any specified signal, or by default the termination signal, to one or more processes. The PID must be specified as the argument.

The following are some examples of implementing kill signals. To terminate a process with ID 921 gracefully:

# kill 15 921

Failing that, to kill the process immediately:

# kill 9 921

Alternatively, to pause rather than remove the process entirely:

# kill 17 921

If you encounter the below error while running the kill command:

kill: command not found

you may try installing the below package as per your choice of distribution:

kill Command Examples

1. To get the list of signals:

# kill -l 
 1) SIGHUP  2) SIGINT      3) SIGQUIT  4) SIGILL
 5) SIGTRAP  6) SIGABRT      7) SIGEMT  8) SIGFPE
 9) SIGKILL 10) SIGBUS     11) SIGSEGV 12) SIGSYS
13) SIGPIPE 14) SIGALRM     15) SIGTERM 16) SIGURG
17) SIGSTOP 18) SIGTSTP     19) SIGCONT 20) SIGCHLD
21) SIGTTIN 22) SIGTTOU     23) SIGIO 24) SIGXCPU
25) SIGXFSZ 26) SIGVTALRM 27) SIGPROF 28) SIGWINCH
29) SIGINFO 30) SIGUSR1     31) SIGUSR2

2. To send a particular signal:

# kill -s 9 

3. To specify the list of processes for kill:

# kill 1234 2345 3456 

4. Terminate a program using the default SIGTERM (terminate) signal:

# kill process_id

5. Terminate a background job:

# kill %job_id

6. Terminate a program using the SIGHUP (hang up) signal. Many daemons will reload instead of terminating:

# kill -1|HUP process_id

7. Terminate a program using the SIGINT (interrupt) signal. This is typically initiated by the user pressing `Ctrl + C`:

# kill -2|INT process_id

8. Signal the operating system to immediately terminate a program (which gets no chance to capture the signal):

# kill -9|KILL process_id

9. Signal the operating system to pause a program until a SIGCONT (“continue”) signal is received:

# kill -17|STOP process_id

10. Send a `SIGUSR1` signal to all processes with the given GID (group id):

# kill -SIGUSR1 -group_id