[regularfry]

Linux itself might not have been (although I'd challenge that if I could remember dates a bit better); Apache and Perl certainly was.

[pjmlp]

In 2000 we were delivering UNIX software into production on Aix, Solaris and HP-UX boxes, my employer at the time did not consider either GNU/Linux or BSD fit for the quality standards we expected from a standard UNIX, although we did use them on some internal servers, including our builds.