You can set this permanently at the terminal with:

  defaults write -g AppleShowAllFiles yes

or to always see the hidden files in the Finder:

  defaults write com.apple.finder AppleShowAllFiles yes

use `defaults` to see and set a number of preferences that are not apparent. Around the turn of the century Mac OS started moving to streamline the UX and making it more difficult to change (and possibly break) things in that process; for better or worse. I remember the discoverability of user settings/preferences and tools/utilities being much easier using the finder and menu bars in the 90's. Now, one is forced to get comfortable with the command line to have that level of control and customization.