So this really is controlled by stty, specifically the [-]tostop option. On my system (which doesn't stop background jobs that try to output), it's off ("-tostop"). I'm guessing that on your system it's on. Try: 

stty -a

[download]

...and see what it is.

In reply to Re^4: How to know if a perl script is put in the background [OT] by kyle
in thread How to know if a perl script is put in the background by rapide

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