zombie_processes.txt

inod in linux : delete old files or change file system

df -i  #inods

ls -li #files with the numbers of inodes

fork()  #start process

statuses of the process: R - running, s- sleep, 
d - awaiting for input/output, t - stopped, z - zombie

@ubuntu1:~$ ps -efl | grep "z.py"
0 S andrii_+  2549  1855  0  80   0 -  5971 poll_s 19:16 pts/0    00:00:00 /usr/bin/python ./z.py
0 S andrii_+  2552  2474  0  80   0 -  3236 pipe_w 19:16 pts/1    00:00:00 grep --color=auto z.py
@ubuntu1:~$ ps -efl | grep 2549
0 S andrii_+  2549  1855  0  80   0 -  5971 poll_s 19:16 pts/0    00:00:00 /usr/bin/python ./z.py
0 Z andrii_+  2550  2549  0  80   0 -     0 -      19:16 pts/0    00:00:00 [ls] <defunct>
0 S andrii_+  2567  2474  0  80   0 -  3236 pipe_w 19:16 pts/1    00:00:00 grep --color=auto 2549
@ubuntu1:~$ ps -efl | grep 2550
0 Z andrii_+  2550  2549  0  80   0 -     0 -      19:16 pts/0    00:00:00 [ls] <defunct>
0 S andrii_+  2607  2474  0  80   0 -  3236 pipe_w 19:16 pts/1    00:00:00 grep --color=auto 2550
@ubuntu1:  kill -9 2549  #kill zombie process

 sudo apt-get install gdb
 
@ubuntu1:~$ sudo gdb -p 2779

(gdb) call wait(2780)

@ubuntu1:~$ ps -efl | grep ls  #zombie killed, but process is in work
0 S andrii_+  3222  2474  0  80   0 -  3236 pipe_w 19:39 pts/1    00:00:00 grep --color=auto ls