For service supervision with runit:

(1) add scripts into /etc/sv/<service>/run

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Example: /etc/sv/nginx/run   |
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#!/bin/sh
mkdir -p /tmp/nginx
exec /usr/sbin/nginx
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Example: /etc/sv/ssh/run     |
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#!/bin/sh
set -e
ssh-keygen -A
exec /usr/sbin/sshd -D
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Example: /etc/sv/tinyssh/run |
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#!/bin/sh
PORT=22
mkdir -p /etc/tinyssh
/usr/sbin/tinysshd-makekey /etc/tinyssh/sshkeys 2>/dev/null
exec tcpserver -HRDl0 0.0.0.0 $PORT /usr/sbin/tinysshd -v -l /etc/tinyssh/sshkeys
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(2) set permissions:

chmod 700 /etc/sv/<service>/run

(3) symlink the script directory to the service directory:

ln -s /etc/sv/nginx /etc/service/nginx

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The socklog package by the same author can provide logging
with built in log rotation & also be managed by runit.