https://stackoverflow.com/questions/25828883/add-a-number-in-fish-script
https://fishshell.com/docs/2.0/commands.html
1set num (math $num + 1)
-->
https://stackoverflow.com/questions/25828883/add-a-number-in-fish-script
https://fishshell.com/docs/2.0/commands.html
1set num (math $num + 1)