The formal way to run mplayer in background.
mplayer some.mkv </dev/null >/dev/null 2>&1 &
[3]9536
[3]9536
means pid of the mplayer command is 9536.
If i replace &1 with 1 for the above command:
mplayer some.mkv </dev/null >/dev/null 2>1 &
[4] 9590
[3] Done mplayer some.mkv < /dev/null > /dev/null 2> 1
Why got the extra output here?
[3] Done mplayer some.mkv < /dev/null > /dev/null 2> 1
It's not related to your change. This happened because your previous mplayer
instance exited in the mean time. Here's another example:
$ sleep 1 &
[1] 18155 # Sleep #1 started in background
$ sleep 1 &
[2] 18163 # Sleep #2 started in background
[1] Done sleep 1 # Sleep #1 finished because it's been a second
Replacing 2>&1
with 2>1
makes mplayer status and errors go to a file named 1
in the current directory. I don't know why you would do such a thing, but bash is happy to oblige.