Firefox

about:config

Set all the things at once using user.js. First, download user.js, then run:

firefox_dir=~/.mozilla/firefox/
profiles=$(grep ^Path $firefox_dir/profiles.ini  | cut -d= -f2)
for profile in $profiles; do
  target=$firefox_dir/$profile/user.js
  cp user.js $target
done

Password Manager

chrome://passwordmgr/content/passwordManager.xul