Title: Port of the week: checkrestart

	Title: Port of the week: checkrestart
	Author: Solène
	Date: 02 March 2021
	Tags: openbsd portoftheweek
	Description:

	# Introduction

	This article features the very useful program "checkrestart" which is
	OpenBSD specific. The purpose of checkrestart is to display which
	programs and their according PID for which the binaries doesn't exist
	anymore.

	Why would their binary be absent? The obvious case is that the program
	was removed, but what it is really good at, is when you upgrade a
	package with running binaries, the old binary is deleted and the new
	binary installed. In that case, you will have to stop all the running
	binaries and restart them. Hence the name "checkrestart".

	# Installation

	Installing it is as simple as running pkg_add checkrestart

	# Usage

	This is simple too, when you run checkrestart, you will have a list of
	PID numbers with the binary name.

	For example, on my system, checkrestart gives me information about what
	programs got updated that I should restart to run the new binary.

	```
	69575 lagrange
	16033 lagrange
	9664 lagrange
	77211 dhcpleased
	6134 dhcpleased
	21860 dhcpleased
	```

	# Real world usage

	If you run OpenBSD -stable, you will want to use checkrestart after
	running pkg_add -u. After a package update, most often related to
	daemons, you will have to restart the related services.

	On my server, in my daily script updating packages and running
	syspatch, I use it to automatically restart some services.

	```
	checkrestart \| grep php && rcctl restart php-fpm
	checkrestart \| grep postgres && rcctl restart postgresql
	checkrestart \| grep nginx && rcctl restart nginx
	```

	# Other Operating System

	I've been told that checkrestart is also available on FreeBSD as a
	package! The output may differ but the use is the same.

	On Linux, a similar tool exists under the name "needrestart", at least
	on Debian and Gentoo.