On Arch Linux, how do I allow a user to use `sudo` for a specific command without that user having to use their password?  Say for example, allowing a user `josh` to use the `systemctl ...`.  It would be even nicer if the user can only use specific sub-commands of `systemctl` such as `systemctl start/stop/status`
To allow a user to use `sudo` for a specific command without having to enter their password on Arch Linux, you can edit the sudoers file using the `visudo` command.

1. Open a terminal and run the command `sudo visudo`. This will open the sudoers file in the nano text editor.

2. Add the following line to the end of the file to allow the user josh to run the systemctl command without a password:

```javascript
josh ALL=(ALL) NOPASSWD: /usr/bin/systemctl start, /usr/bin/systemctl stop, /usr/bin/systemctl status
```
This line allows the user josh to run the systemctl start, systemctl stop and systemctl status commands as the superuser without having to enter a password.

3. Save the changes to the file by pressing `Ctrl+X`, then `Y`, and then `Enter`.

Now, the user josh can use the `sudo` command with the specified `systemct` sub-commands without being prompted for a password. It is important to note that editing the sudoers file can be dangerous and should be done with caution.
I wrote a macro for Vim which automatcially adds users to the sudoers file.  How do I configure `visudo` to open Vim?
To configure visudo to open Vim when you use the command, you will need to edit the sudoers file. You can do this by running the command sudo visudo. This will open the sudoers file in the nano text editor.

At the bottom of the file, add the line EDITOR=/usr/bin/vim, and then press Ctrl+X, then Y, and then Enter to save the changes. Now, when you use the visudo command, it will open the sudoers file in Vim instead of nano.