Re: psql -f and PAGER

On 2022-03-29 19:08:44 -0700, David G. Johnston wrote:
> On Tue, Mar 29, 2022 at 6:30 PM Paul Jungwirth <pj@illuminatedcomputing.com>
> wrote:
>
>     I noticed that this runs your pager:
>
>          psql -f <(echo 'select * from pg_class;')
>
>     but not this:
>
>          echo 'select * from pg_class;' | psql
[...]
>
> For both examples:
> pager defaults to on
> the output of the psql session is a terminal
> the full contents of pg_class are not going to fit on one terminal screen
> ergo, the output of select * from pg_class; should be piped to the pager in
> both cases

This is incomplete in the docs. The pager is also not called if stdin is
not a terminal (which makes sense - you couldn't control the pager).

So
    echo 'select * from pg_class;' | psql
doesn't call the pager. Neither do:
    psql -f <(echo 'select * from pg_class;') < /dev/null
    psql -f <(echo 'select * from pg_class;') > /dev/null

But
    psql -f <(echo 'select * from pg_class;')
does, since both stdin and stdout are a terminal.

        hp

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