<Snader_LB>
aiui, the output of the command in "<(...)" is taken as a file name, and that file name is given as an argument to the command standing before the "<(...)" ("gem cert --add", in this case)
<Snader_LB>
no, not the output; the FIFO file name, which contains the output
<Snader_LB>
got it
<Snader_LB>
still, it won't work in any shell, e.g., dash(1) does not support it, which is /bin/sh on Debian based systems
<Snader_LB>
so in that sense, it might still be better to split the command in two commands: one for downloading the file to a temporary file, and one for importing that file using "gem cert --add <file>"
<Snader_LB>
(and the real question would be, why gem(1) can't read such file from standard input)