99% of shell scripts are just executables that have a shebang line at the top. As a rule of thumb, the only time when using a posix-compatible shell as your int

99% of shell scripts are just executables that have a shebang line at the top. As a rule of thumb, the only time when using a posix-compatible shell as your interactive shell matters is when you are expected to "source" or "eval" a sh script that is generated by some other program (as the virtualenv example)