Re: Piping and Redirection

[Hans Boldt <boldt@xxxxxxxxxx>]

Dennis Lovelady wrote:
> For the record, OVRDBF ... TOFILE(...) is precisely what redirection is
> about.
>
> But it stops there, unfortunately.
>
> Piping is the ability to stream the output one process as the input of
> another.  On the AS/400 (ignoring QSH if I may be so bold), this simple
> example:
>     sed 's/a/b/g' filename | grep 'any' | tee def | more
>
> would be executed something like this (assuming that sed and grep and tee
> actually exist)   :
>
> ovrdbf input TOFILE(filename)
> ovrdbf output TOFILE(qtemp/stream1)
> call sed 's/a/b/g'
> ovrdbf input TOFILE(qtemp/stream1)
> ovrdbf output TOFILE(qtemp/stream2)
> call grep 'any'
> ovrdbf input TOFILE(qtemp/stream2)
> ovrdbf output TOFILE(def)
> call tee
> /* (existing overrides will suffice here...) */
> call more
>
> Kinda loses the beauty and simplicity.
>
> Dennis
Just another difference: In Unix, the commands can run in separate
processes running simultaneously. And so that OS/400 command
sequence isn't quite the same.

Cheers!  Hans