Re: Problem with 'rm -i' in ksh

On 12.01.2025 15:14, Kenny McCormack wrote:

In article <vm0ela$15i9h$1@dont-email.me>,
Janis Papanagnou  <janis_papanagnou+ng@hotmail.com> wrote:
...

It's called in a (ksh-)function within a structure like this
>
 function f { ... rm ... }
 p1 | p2 | while read ... do ... f ... done
 f

 
When you are in a "... | while read" loop, the stuff inside the while loop
has stdin coming from the pipe.

First I thought you meant bash's sub-shell issue (which isn't present
in ksh). But you are right about stdin; I completely missed that. Doh!
Thanks for spotting that!

Yes, I've been bitten by this a few times,
and it is one of the (many) reasons I avoid the "... | while read" idiom.
There are always better/cleaner alternatives.

(I know that you can circumvent bash's sub-shell issue with while/read
e.g. by using process substitution

  while read ... do ... f ... done < <( p1 | p2 )

But - in case you were thinking about that idiom - that would not solve
the redirection issue.)

One way to fix the redirection issue would be to duplicate the 'stdin'
file descriptor; to start the script with
  exec 4<&0
and then call the remove command referring explicitly to that other FD
using
  0<&4 /bin/rm -i ...

What (other, "better/cleaner") idioms were you thinking of?

Janis