Practical Linux - Part 08 - Process & Memory System | 进程与内存系统

Oct 16 - Process & Memory System
- What is process:
  - execute program
    - PID
    - UID/GID
    - example: bash
  - parent process & child process
    - example bash <enter> ps -l
    - fork & exec system call
  - daemon
- Multi-processing
  - multiple online user
  - multiple processes
  - - tty1~7
- Process Control
  - foreground & background
    - ctrl + c
  - <command> &
  - <command> > /tmp/log.txt 2>&1 &
  - stop ctrl + z
  - jobs
  - fg [jobid]
  - bg [jobid]
  - kill -signal %jobid
    - kill -l
    - 1, 2, 9, 15, 19
  - killall
  - nohup <command> &
  - ps
    - ps aux
    - ps -lA
    - ps axjf
    - ps -l
      - STAT - http://askubuntu.com/questions/360252/what-do-the-stat-column-values-in-ps-mean
  - top
    - load = processes using or waiting for CPU
    - PR = priority. PR = NI + 20
    - NI = Nice. the higher, the nicer
  - renice [nice] <PID>
  - free
  - /proc
    - uptime
    - version
    - vmstat
    - zoneinfo
  - lsof
- Assignment
  - log on your amazon vm
  - make sure your vm has the following to process in the background even you log out:
    - a running process running sleep 1209600 && echo "finally I'm awake. goodbye" > ~/log.txt
    - a stopped process running ping localhost

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