Kill zombie process under Ubuntu

1. Install the pstree package

1. On Mac OS

  brew install pstree

2. On Fedora/Red Hat/CentOS

  yum -y install psmisc

3、在 Ubuntu/Debian

 apt-get install psmisc

2. Check the dead process

 ps aux | grep 'Z'

3. Clear the dead process

 kill -9 PID