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Play Audio in Background?
Authored by: MacTipper on Oct 03, '08 09:35:28AM

That only somewhat works. I can continue working in that same terminal window, however, if I close it, I get a warning saying that I'm going to terminate running processes (login, bash, afplay)

My command:

afplay /Users/Shared/iTunes/iTunes\ Music/Aaron\ Shust/Whispered\ and\ Shouted/01\ Long\ Live\ the\ King.mp3 &



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Play Audio in Background?
Authored by: VxJasonxV on Oct 03, '08 09:56:58AM

Don't worry that you're doing something wrong. You're correct. Using & puts it in the background of the shell, but if you kill the shell, you kill that application as well.

(Applications don't run without a controller of some manner.)

You have two options, and both may be a bit more involved than you want to be.

One is that you can use the 'nohup' command to continue command execution even if the shell goes away. Or you can learn how to use the 'screen' command.

nohup will continue command execution until completion (or failure, either way a program exit), and then it'll go away.
screen is a "terminal multiplexer", it allows you to turn one terminal into many all self contained. It serves an excellent second purpose that if you're doing something (say, ssh'ed into a remote server) and your connection goes away, everything you were doing inside screen continues to run, or everything you have done remains there in context until you reconnect to the server and resume screen.
This of course works locally. Be forewarned this is a VERY extreme example. If you're running screen, and terminal crashes, nothing happens to screen. It's all still there to reconnect to when you re-open Terminal and reconnect to it.
The only thing screen doesn't do is survive a reboot (go figure).

It'll take a little bit of learning to get used to it (the man page is VERY big), but I absolutely swear by screen.



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Play Audio in Background?
Authored by: rcbarnes on May 12, '12 04:23:45AM

There's an easier way to close a terminal window (which is not the preferred way to end the shell inside it---similar to using 'force quit' to end safari instead of the quit menu command) without OS X whining or killing the programs you've started:

Instead of ending a command with '&', end it with '& disown' (no quotes, of course).

Note: This will work for essentially *any* program, but if there are semi-colons (;) in the line you typed, you are running more than one program and simply adding ' & disown' to the end of the line may not be sufficient to get the behavior you want.

I am sure the OP gave up on this page long ago, but in case future readers who stumble on this page are daunted by your suggestions (valid though they are), I though this very simple fix would be useful.



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Play Audio in Background?
Authored by: corienti on Oct 03, '08 02:45:25PM

This is a little complicated - the full details are far too involved to go into right here.
However, the bottom line is that you can control whether a shell's subprocesses (bash = your shell) are terminated, when the shell is terminated.

By default, I don't think bash itself terminates its backgrounded children, when you exit bash (by typing control-D or exit).
That is, it does not terminate its children on my system, but I've long forgotten if that was something I configured myself, or the default behavior. I think it's default behaviour though - pretty sure.

However, from just testing now, it appears that if you click the red "close" button, Terminal itself terminates bash AND its children for you.

So the simple solution might be to close your shell by typing "exit" or control-D instead of clicking the close button.

What actually happens when you click the red "close" button is that the system sends a TERM (exit) signal to the shell - and when bash receives a TERM signal, it sends a TERM to all of its children before it exits itself.
However when you terminate bash by typing "exit" or control-D, it doesn't send a TERM to its children.

nohup and screen are not needed.
ksh also does not terminate its children by default when exiting, and nohup is needed.
Whether bash does or not is definitely configurable.

There's a lot I'm not explaining here but as you can see it would run into pages and pages and pages if I tried to explain it all here now!

If you read a few man pages (particularly of bash) and do a bit of testing you should be able to get it to do what you want.



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Play Audio in Background?
Authored by: yogiken on Aug 05, '10 11:04:21AM
There is a simpler way to run a program in the background and detach it from the controlling terminal without using nohup. Just do this.

(afplay song.mp3&)

The parentheses request the creation of a subshell which becomes the parent process for the program you run. You can verify this works as follows.


(sleep 60&)
ps aux|grep sleep

You'll see something like this.


you      44389   0.0  0.0  2426564    324 s001  SN   11:00AM   0:00.00 sleep 60
you      44395   0.0  0.0  2425712    280 s001  R+   11:00AM   0:00.00 grep sleep

(Ignore the grep sleep which is the command you just ran.) A minute later, the same ps/grep will reveal that the program has terminated (and so has the parent subshell).

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