How to create a custom systemctl command?

I created the

mycommand.target

[Unit]
Description=Mycom
Documentation=man:systemd.special(7)
DefaultDependencies=no
Requires=systemd-mycom.service
After=systemd-mycom.service
StopWhenUnneeded=yes

systemd-mycom.service

[Unit]
Description=Mycom
DefaultDependencies=no
Requires=other.target
After=other.target

[Service]
Type=oneshot
ExecStart=/path/to/my/file.sh

file.sh

#!/bin/bash
rm /etc/some/stuff

this is just a test command, but the actual stuff is far complex

When I tried to run the command via:

sudo systemctl Mycom

I get the following error:

Unknown operation Mycom

How do I properly create a new systemctl command?

When you use systemctl you have to use it like this, as root:

systemctl start # starts the service        
systemctl stop # stops the service         
systemctl enable # starts the service on start-ups        
systemctl restart # restarts the service     

That's why you're getting unknown command error. You should use sudo systemctl start Mycom.