> > read all my variables < my.input.file
> >
> > If you need to read several lines, use exec:
> >
> > exec 3<&0    # save old stdin to unused file descriptor 3
> > exec < my.input.file  # make my.input.file stdin
> > read line1
> > read line2
> > read line3
> > exec <&3    # get back original stdin
> > exec 3<&-   # and close fd 3.
>
>Thanx, that will work.
>
> > > There is redirection to duplicate input or output to some file
> > > descriptor (10<inpfn , 11>outpfn), but I do have no clue whatsoever what
> > > these file descriptors are used for and how.
> >
> > 0 is stdin, 1 is stdout, and 2 is stderr.  The rest are yours to
> > play with as you need.
>
>That's what I thought, but what can you do with them?  None of the bash
>commands uses a file descriptor as argument.  In the example you give,
>you use them as a temp var to store the standard I/O files.  Is there
>anything else?

You can do something like:

exec 10< datafile

and then later

read var1 var2 var3 ... <&10

will read the next line from descriptor 10, which is connected to the datafile.

You could also use ksh instead of bash; its "read" command has a -u option to specify a one-digit descriptor number.

Barry Margolin

documented on: 2000.12.20 Wed 12:56:54