On Sun, Nov 02, 2008 at 08:53:15AM +0000, Stephane Chazelas wrote:
> On Sat, Nov 01, 2008 at 11:21:01PM -0000, Sven Mascheck wrote:
>> - It actually works (also on Ultrix) but it is not robust
>> in any traditional Bourne shell (except where fixed by the vendor):
>>
>> $ echo x y > file1 > file2 # ok, all output in file2
>> $ echo x > file1 y > file2 # not ok, all output in file1 instead of
>> file2
> is it the order of the redirections that is not respected in
> those old Bourne shells, or is it that only some of the
> redirections are performed?
It looks as if just the order is wrong.
> Would
> : > file1 > file2
> or
> : > file1 x > file2
> create (and truncate) both file1 and file2 in any case?
Good idea, but:
a) : > file
V7 ... SVR1: file not created
SVR2: file created
(probably due to: svr2 fixed redirection of built-ins generally)
b) : > file1 x > file2
(like above, no files created)
c) echo x > file1 y > file2
V7...SVR2: all output in file1, and: file2 truncated
> Would that fork a process, BTW in those old shells?
Not with the null command.
> Maybe a better way would be
> exec 3> file1 3> file2 3>&-
> (to truncate those files)
This actually truncates both files in V7, Sys3, SVR1 and SVR2.
--
Sven
