this post was submitted on 11 Aug 2023
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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
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Huh, I always thought su stands for super user, but apparently it actually stands for substitute user (according to the manpage)
I don't think "substitute user" is the original meaning, and it's more like a retroactively applied acronym.
Looking at various old Unix manpages, it said various things in the past. In the HP-UX documentation it even lists three different variants in the same man page: "switch user", "set user" and "superuser".
"superuser" is probably the original meaning, because that's what it says in the Unix Manual 1st edition (1971): http://man.cat-v.org/unix-1st/1/su
I love Unix archeology :)
Wouldn't the password remain in the shell history? Or didn't that exist back then?
It probably wasn't such a concern back in 1971. I mean, even nowadays you still find programs where you can just add a login password to the command line.
Wow, that's terrible for security.
You can do
su
to change the user in the current shell. Afaik it just defaults to root if no user ist specified. Everytime you runsu
you actually dosu root
That said I always thought that it stands for switch user so intereresting to know that it‘s substitute.
I've heard people call it superuser since before Linux (AIX Unix a long time ago for example).
But substitute user makes sense since you can su to any user (just root is the default).