SOURCE_STR currently includes the value of $HOME (at install time).
Change SOURCE_STR to include a literal "$HOME" (to be expanded at
profile runtime) so that sourcing nvm will work if the user changes
their username, shares their profile, et cetera.
Also use the more portable single-square-bracket test.
The git:// transport is vulnerable to man-in-the-middle and DNS
spoofing attacks and its use over untrusted networks should be
discouraged.
Change to the https:// clone url in the install instructions.
Fraser Tweedale