A programmer's unorganized notes for everyone's reference
Note: I would not recommend installing any special program to fix any issues as they are useless at best, and malicious (virus-laden) at worst.
If you still really want to install something, you can install an antivirus program, but keep in mind that an antivirus may dramatically slow down your computer are not very useful as the default Apple configurations is already very secure.
Links: official instructions, another useful unofficial guide
You should do if your computer is slow to startup. Common offending programs are various Adobe apps, Zoom, and Spotify. Note that these programs try to re-enable startup at boot each time they update, so you may have to go into their respective settings to disable the startup (see this guide for Spotify, for example)
Links: official instructions
Spotlight is macOS's global searching tool that lets you search through all your files. It stores an index into all your files to speed up the search, but it needs to build an index first. If you're recently updated macOS or have moved a lot of files onto your disk recently, Spotlight will have to read through all those files and (re-)build its index in the background, which will slow down your computer in general. Sometimes if the index is corrupted, Spotlight might repeatedly try to fix it (but fail).
There are two simple fixes:
These are useful if you've updated your macOS recently and you feel like your touchpad, keyboard, monitor, camera or mic are having issues. Sometimes, subtle software issues magically resolve themselves with these resets. Given that they are fairly safe (you will lose the volume and brightness settings mostly), they are good to do.
Links: official instructions
Links: official instructions
Tested on: Debian 10 “Buster”, Raspbian
/etc/systemd/system/<filename-without-spaces>.service
/etc/systemd/system/<filename-without-spaces>.timer
[Unit]
Description=<<Some description>>
After=network.target
[Service]
ExecStart=<<command here>>
WorkingDirectory=<<working directory>>
StandardOutput=inherit
StandardError=inherit
Restart=always
User=<<user name>>
[Install]
WantedBy=multi-user.target