Not sure if that's cheating - most of the suggestions on this page go from the original version of something. A kind of 'Ship of Theseus' problem - there's no natural or obvious definition of 'what counts as still the same thing' (except 'all parts exactly the same', I guess).
Wikipedia says grep is from 1974.
Cat, chmod, chown, comp, cp, date, df, du, ed, find, ln, ls, mailx, mkdir, mv, nm, od, pr, rm, rmdir, sort, strip, tty, unlink, wc, who, and write are from Version 1 Unix - Nov 1971!
The page for ed says: "It was one of the first parts of the Unix operating system that was developed, in August 1969."
Wikipedia says grep is from 1974.
Cat, chmod, chown, comp, cp, date, df, du, ed, find, ln, ls, mailx, mkdir, mv, nm, od, pr, rm, rmdir, sort, strip, tty, unlink, wc, who, and write are from Version 1 Unix - Nov 1971!
The page for ed says: "It was one of the first parts of the Unix operating system that was developed, in August 1969."
https://en.wikipedia.org/wiki/Ship_of_Theseus
https://en.wikipedia.org/wiki/List_of_Unix_commands