Kill Me Softly

Kill processes in a reliable manner.

Purpose

An incredible number of times, I had to perform a simple task: killing a process, and making sure the process was dead before proceeding.

Sometimes the process doesn't die by SIGTERM, and you need to send a SIGKILL.

In some (rare) situations, the process doesn't die by SIGKILL either.

Sometimes the process just takes some time to die.

By the way, what I usually want is something like hey, kill this process and don't go on until it's dead.

It's stupid, but it's everything killmesoftly does; it tries to send a SIGTERM to a process, if it doesn't die within 15 seconds it sends a SIGKILL, if it still doesn't die it reports it.

AFAIK there's no other tool to do that, even though such logic is implemented in a lot of software and service scripts.

Usage

You can feed the two scripts with process names (or matching expression, that will be sent to pgrep) or PIDs, respectively.

The approach is blocking by design: the script won't exit until the process is actually dead, and latter PIDs or names won't be killed until previous ones are dead.

If there's an error on one parameter (e.g. you've specified a name which matches more than one process, or a non-existent PID) the scripts will go on with the other parameters; on the contrary, if there's an hard error (e.g. a process that doesn't exit on a SIGKILL) the whole kill chain will be stopped and an error will be returned.

The default timeout is 15 seconds. It's currently hardcoded.

kmsn

Kill processes softly by name matching pattern.
Usage:
kmsn first_pgrep_pattern [second_pgrep_pattern] <...>

kmsp

Kill processes softly by pid number
Usage:
./kmsp first_pid_to_kill [second_pid_to_kill] <...>

Requirements

Those should be available on almost any Linux system, even on minimal installs:

• Linux
• Bash
• Kill and pgrep executables (e.g. procps package on Ubuntu/Debian)
• readlink (e.g. coreutils on Ubuntu/Debian)
• proc filesystem

Install

Just clone this repository, or download a packed zip, put kmsp and kmsn in your path, set them executable, make sure kms_functions is in the same directory, and you're ready to go.

License

This is Apache-2.0 licensed, which is the most permissive license I could think of. Feel free to include and modify this code however you like.

TODOs

• OSX and/or *BSD support
• a --all switch for kmsp that allows killing all processes that match a certain parameter
• consider whether we should return different exit codes in the event some parameters are wrong; currently we return a nonzero exit code only on zero-parameters passed or hard failures.
• allow specifying a different signal rather than SIGTERM for soft kill, and/or additional signals to be sent before/after SIGTERM.
• configurable timeouts
• consider transforming such scripts in a set of functions that can be sourced, rather than used as executables
• add options for killing process groups and/or check whether children have actually exited