The problem happened on one of my local machines with CentOS 6. I ssh to it from my MacBook trying to test a script, which is in /usr/local/bin. However, whenever I tried to execute the command, it is immediately suspended, displaying "+ Stopped". I had to use
fg to make it the foreground. Since it's 3 a.m. in the morning, I was wondering if it is related to nice. But I tried some command with nice and renice, it didn't work. As the script calls an I/O-bound Perl script, I also tried ionice but it didn't work either.
It seems difficult to reproduce the problem, since after a reboot the problem is gone. Does anyone know the reason?