Linux

in terms of bits, what is the width of a User ID? seems like I remember it being 32-bit (maybe wrong) but I can't find anything anywhere on ther subject.

It's 2 bytes, I guess...

Hi !
Look at this :

Code:

     UID     Automatically generated or your choice.  It must be less than
             32000.

This is what I found in the "adduser" manual page.
As long as the UID must be under 32000, I'm sure that it is an int value, and that means 2 bytes (on most of the computers).
So, I gues that this answered your question
Bye !

yeah thank you for the reply, I have a follow up question.

it says it must be below 32k

well I did some math and 2^15 is 32768, so I'm assuming that's where they're getting it from.

since it's 8 bits (1 byte) followed by 7 bits, I'm assuming the 16th bit is being used as a sign bit.

if it is a signed bit, then that begs the question: "When would it be deemed appropriate to give someone a negative userID?"

Some systems do in fact use negative uids, for example on some flavours of GNU/Linux -1 is used for the "nobody" user.