Re: Files and pipes only?

[Scott W. <sw...@ch...>]

Ethan A Merritt wrote:
> On Sunday 17 February 2008 02:22, Scott Worley wrote:
>> gnuplot <<< 'plot "'<(echo -e '1\n3\n2')'" with lines; pause 10'
> 
> Which one of those two redirections is causing the error?

The <() redirection.  The above effectively becomes

    gnuplot <<< 'plot "/dev/fd/63" with lines; pause 10'

(as demonstrated by replacing "gnuplot" with "cat":

    $ cat <<< 'plot "'<(echo -e '1\n3.5\n2')'" with lines; pause 10'
    plot "/dev/fd/63" with lines; pause 10
    $ ls -l <( echo foo )
    crw-rw-rw-  1 root  wheel   22,  63 Sep 23  2005 /dev/fd/63

) and then gnuplot refuses to read from /dev/fd/63 because it's neither 
a file nor a pipe in *BSD.


This syntax used to work because in earlier versions of bash <() was 
implemented with named pipes in /tmp.  Under bash 3.1:

    $ cat <<< 'plot "'<(echo -e '1\n3.5\n2')'" with lines; pause 10'
    plot "/var/tmp//sh-np-3368567213" with lines; pause 10
    $ ls -l <( echo foo )
    prw-------  1 chkno  wheel  0 Feb 17 08:34 /var/tmp//sh-np-1203260826