But what source code debuggers did they have available? Other than gdb, I can't name any Unix C source code debuggers. I believe they were working on Unix befo

But what source code debuggers did they have available? Other than gdb, I can't name any Unix C source code debuggers. I believe they were working on Unix before GDB was created (wikipedia says gdb was created in 1986 - https://en.wikipedia.org/wiki/Gdb https://en.wikipedia.org/wiki/Gdb). Plan 9 has acid, but from the man page and english manual, the debugger is closer to cli/tui than gui. see https://9fans.github.io/plan9port/man/man1/acid.html https://9fans.github.io/plan9port/man/man1/acid.html and https://plan9.io/sys/doc/acid.html https://plan9.io/sys/doc/acid.html