What System V did to the poor
On V7, UCB BSD 4.x, SunOS 2.x, 3.x and 4.x, the *BSDs, Linux, and anything using GNU fileutils:
; touch a b ; ln a b && echo oops ln: b: File exists
On System V, including Solaris 8:
; touch a b ; ln a b && echo oops oops
That's right: the System V version of
ln goes to significant
extra work over just calling
link(2), and in the process is so
unhelpful that people had to make a new utility called
to do the right thing. (Fortunately, this behavior
is no longer SuS compliant, per the ln spec.)
This is one of those things that sticks in my mind, because I had the
distinction of being the first person to try to run CNews on a System V
machine. CNews has a lot of shell scripts and had been developed on V7
and BSD systems, so all of the shell scripts did their locking with '
temp LOCK'; the consequences of the locking not actually working were
reasonably spectacular and quite memorable. Fortunately the machine
wasn't being used by anyone else at the time.
(The authors of CNews were as appalled as I was, and promptly introduced
newslock program and switched the shell scripts to using it,
so they had behavior they could count on.)
I was reminded of this mess recently when I wrote a shell script that needed to both do locking and run on our Solaris 8 systems. I was reasonably displeased to discover that Solaris 8 still has this bit of braindamage.