This should handle installation scenarios we can handle with
anything resembling confidence. Goal is approximating the existing
setup--not enforcing a best-practice...
Approaches (+ installer-handled, - manual) and configs each covers:
+ no change needed; /nix OK on boot volume:
All pre-Catalina (regardless of T2 or FileVault use)
+ create new unencrypted volume:
Catalina, pre-T2, no FileVault
+ create new encrypted-at-rest volume:
Catalina, pre-T2, FileVault
Catalina, T2, no FileVault
- require user to pre-create encrypted volume
Catalina, T2, FileVault
The current behaviour modifies the first writeable file from amongst
.bash_profile, .bash_login and .profile. So .bash_profile (if it is
writable) would be modified even if a user has already sourced nix.sh
in, say, .profile.
This commit introduces a new environment variable,
NIX_INSTALLER_NO_MODIFY_PROFILE. If this is set during installation,
then the modifications are unconditionally skipped.
This is useful for users who have a manually curated set of dotfiles
that they are porting to a new machine. In such scenarios, nix.sh is
already sourced at a place where the user prefers. Without this
change, the nix installer would insist on modifying .bash_profile if
it exists.
This commit also add documentations for both the current behaviour and
the new override.
