Linux process command help (part 3)

Hi, for each command I need to explain what the command does and then show some of the output

For example:

ps << this command shows the running process

PID TTY TIME CMD

1250 pts/5 00:00:00 bash

1500 pts/5 00:00:00 ps.

The commands that I need solved are:

$ ps -e -o pid,uname,pcpu,pmem,comm

$ ps -e -o pid,uname=USERNAME,pcpu=CPU_USAGE,pmem,comm

$ ps -e -o pid,comm,etime

$ watch -n 1 'ps -e -o pid,uname,cmd,pmem,pcpu --sort=-pmem,-pcpu | head -15'