27 Jun
2016
27 Jun
'16
4:31 p.m.
Clem Cole <clemc(a)ccc.com> wrote:
A few years later, I did switch to typing to the csh
when I got to UCB, but
that was not until after the MIT job control stuff had been spliced into
the BSD kernel (Horton & Kleckner were probably the ones that convinced me
to learn it). With job control I became a fan, but never warmed up to the
programming syntax. I picked up the mantra that I still consider wise --
"type to Joy and program to Bourne." This is comfortable for the ROMS in
the muscles of my fingers, but my scripts are portable.
Job control of course was an important improvement. I took the idea and
implemented in my bsh in 1985.
Now looking back, it is interesting, that there are just four shells that
implement support for vfork():
- csh - the first
- bsh since 1985
- ksh vfork() probably since 1984, jobcontrol apparently since 1982.
- bosh (my recent Bourne Shell) since 2014
But on a decent OS, vfork() helps a lot to speed up the shell.
On Solaris, fork() is copy-on-write based but still 3x slower than vfork().
Jörg
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