$ ls -lah
total 12K
drwxr-xr-x 1 atom atom  54 Oct  1 00:31 .
drwxr-xr-x 1 atom atom 226 Sep 21 23:42 ..
-rwxr-xr-x 1 atom atom 101 Oct  1 01:00 check
-rw-r--r-- 1 atom atom   0 Oct  1 00:19 down
drwxr-xr-x 1 atom atom  32 Sep 20 12:59 log
-rw-r--r-- 1 atom atom   6 Oct  1 00:59 pid
-rwxr-xr-x 1 atom atom  92 Oct  1 00:59 run
drwx------ 1 atom atom  52 Oct  1 00:59 supervise
[i][0]$ sv check test.service
timeout: run: test.service: (pid 16231) 437s, normally down
[i][1]$ cat check
#!/usr/bin/env sh

exec 2>&1

tail pid | xargs -I '{}' kill -0 '{}'

echo "Checking"
echo meow >meow