If you have a slow-starting program, you can use named pipes as its stdin/stdout. Then write a little script that writes to the inpipe and reads from the outpip

If you have a slow-starting program, you can use named pipes as its stdin/stdout. Then write a little script that writes to the inpipe and reads from the outpipe (interleavedly, so as not to fill up the pipe buffer, I think that's about 4k or so). Now that little script starts up "instantly" compared to the original slow-starting program. http://mywiki.wooledge.org/NamedPipes http://mywiki.wooledge.org/NamedPipes shows an outline of it. http://mywiki.wooledge.org/ProcessManagement#I_want_to_process_a_bunch_of_files_in_parallel.2C_and_when_one_finishes.2C_I_want_to_start_the_next._And_I_want_to_make_sure_there_are_exactly_5_jobs_running_at_a_time http://mywiki.wooledge.org/ProcessManagement#I_want_to_proce.... is another neat trick: when a background process ends, make it echo to some pipe, some other "controller" process is continually reading from that pipe. Since the read is blocking, it'll wait patiently for the echo until it does whatever it should do (maybe even based on whatever it read from the pipe). So much less hacky than sleep-polling :-)