'ps -ef' is standard syntax;
'ps -aux' is BSD syntax.
They are all the sames to display the process status.
eg:
test 7291 0.0 0.0 103332 928 pts/0 S 15:39 0:00 grep 123.py
test is user of OS;
7291 is the process ID;
0.0/0.0 are usages of CPU and Memory;
103332 means number of Virtual Set Size;
928 means number of Resident Set Size;
pts/0 means TTY device;
S means the process is sleeping.
15:39 means starting time;
0:00 means running time;
'grep 123.py' is the processing name.
test 7291 0.0 0.0 103332 928 pts/0 S 15:39 0:00 grep 123.py
test 7291 0.0 0.0 103332 928 pts/0 S 15:39 0:00 123.py
There is two processes. they are all run in your process, but now, it may be sleep or terminated.
I suggest you use command 'man ps' to get more help in linux.