How does Debian allow user to execute commands?

Established monitoring and munin rrdcached.
But I do not understand how to run rrdcached on behalf of the user munin.
The munin user is created automatically when you install munin.

Installed programs:
apt install munin munin-node rrdcached -y

for example we try to create a file named munin:
su - munin -c "touch /tmp/test.txt"

In the end, the file is not created.

vipw
munin:x:112:117:munin application user,,,:/var/lib/munin:/bin/false
June 10th 19 at 16:32
1 answer
June 10th 19 at 16:34
sudo -u munin touch /tmp/test.txt
In fact, the question was not that, I did what wrote above, and su or sudo is the same (in this case)! I need something to register using usermod, but I don't know! Yet decided the question, so: start from the root, and then ruled by the permissions on the file, but it doesn't feel right. - toni26 commented on June 10th 19 at 16:37

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