I have a program which produces useful information on
stdout but also reads from
stdin. I want to redirect its standard output to a file without providing anything on standard input. So far, so good: I can do:
program > output
and don't do anything in the tty.
However, the problem is I want to do this in the background. If I do:
program > output &
the program will get suspended ("suspended (tty input)").
If I do:
program < /dev/null > output &
the program terminates immediately because it reaches EOF.
It seems that what I need is to pipe into
program something which does not do anything for an indefinite amount of time and does not read
stdin. The following approaches work:
while true; do sleep 100; done | program > output & mkfifo fifo && cat fifo | program > output & tail -f /dev/null | program > output &
However, this is all very ugly. There has to be an elegant way, using standard Unix utilities, to "do nothing, indefinitely" (to paraphrase
man true). How could I achieve this? (My main criteria for elegance here: no temporary files; no busy-waiting or periodic wakeups; no exotic utilities; as short as possible.)