https://research.swtch.com/shmacro
The Bourne shell thus adopted ALGOL syntax, distinct from anything else in UNIX.
David Korn brought a pile of C, and wedged it into a max 64k program space (for Xenix), and his upward-compatible Korn shell (ksh88) had many, many features.
Then there were the "UNIX Wars"...
https://en.wikipedia.org/wiki/Unix_wars
The fallout of this was the choice of a few Korn features, but not all (no arrays, coprocesses, [some] eval, regex, et al.)
The wars defined the POSIX shell. Yes, it can be infuriating.
https://research.swtch.com/shmacro
The Bourne shell thus adopted ALGOL syntax, distinct from anything else in UNIX.
David Korn brought a pile of C, and wedged it into a max 64k program space (for Xenix), and his upward-compatible Korn shell (ksh88) had many, many features.
Then there were the "UNIX Wars"...
https://en.wikipedia.org/wiki/Unix_wars
The fallout of this was the choice of a few Korn features, but not all (no arrays, coprocesses, [some] eval, regex, et al.)
The wars defined the POSIX shell. Yes, it can be infuriating.