application/x-sh

A shell script in the unregistered Apache spelling — no standard ever defined a media type for scripts, so .sh files ship under this or text/x-shellscript depending on the server. The bytes are plain text; the meaning is a program, which is why browsers download rather than display it and why serving user uploads under this type is a bad idea. The shebang line (#!) names the interpreter but is not a signature — plenty of valid scripts omit it entirely.

Defined by POSIX Shell Command Language. Registry facts from the IANA media-types registry via mime-db.