Linux CMD

1. Check the version of Python:
   python -V

2. Path of Python:
   python -c "import sys; print sys.executable"

3. Version of Numpy (can be used on other packages):
   python -c "import numpy; print numpy.__version__"

4. Path of Numpy (can be used on other packages):
   python -c "import numpy; print numpy.__file__"

5. Show all the packages with python:
   pip list

6. pip install --upgrade <package name>
   using pip to upgrade python packages

7. pip -V
   version of pip

8. free -m
   check memory usage

$sudo swapon swapfile

9. ctrl + alt + t
   open terminal

10. nvidia-smi
    check GPU memory

11. kill -9 <process id>
    kill the process

12. sudo build/tools/caffe train -solver models/landmark_detection/solver.prototxt --gpu=0,1,2,3 --log_dir=models/landmark_detection/

13. sudo python /data/caffe/python/draw_net.py ./train_val.prototxt ./net.png --rankdir=BT
    draw Caffe model

14. sudo build/tools/caffe train -solver models/landmark_detection/solver_new.prototxt --gpu=0,1,2,3 -snapshot models/landmark_detection/_iter_150000.solverstate (train from a previous state)

15. mkdir <folder name>
    make a new folder

16. pwd
    show current path

17. ls -a
    list all the files and floders

18.cat <filename>
check the content of a file

19. rm -rf <directory>

20. xdg-open (equals to double click on a file)

21. g++ file.c -o filename (how to compile and run c++ code)
    ./filename

22. sudo swapon swapfile (activate memory swap file)

23. ifconfig

24. chmod +x /path/to/yourscript.sh
    make the script executable

25. cd
    cd /root/Docements # 切换到目录/root/Docements
    cd ./path # 切换到当前目录下的path目录中，“.”表示当前目录
    cd ../path # 切换到上层目录中的path目录中，“..”表示上一层目录

26. ls
    -l ：列出长数据串，包含文件的属性与权限数据等
    -a ：列出全部的文件，连同隐藏文件（开头为.的文件）一起列出来（常用）
    -d ：仅列出目录本身，而不是列出目录的文件数据
    -h ：将文件容量以较易读的方式（GB，kB等）列出来
    -R ：连同子目录的内容一起列出（递归列出），等于该目录下的所有文件都会显示出来

27. mkdir

28. ~ (home directory)
    ls ~
    ls ~/path

29. cp (copy)
    cp /path/file . (copy the file to current path)

30. mv (move)
    -rf (remove a directory with files in it)

31. rm (remove)

32. rmdir (remove directory)
    make sure it is empty before remove. otherwise cannnot be removed

33. clear (clear screen)

34. cat (display the contents of a file)

35. less (display a file onto the screen a page at a time)
    /keyword

36. grep <keyword> <file>
    -i : ignore upper/lower case
    'keyword' : search for a phrase
    -v : display lines that are not match
    -n : precede each matching line with the line number
    -c : print only the total count of matched lines

37. wc <file> (word count)
    -w : word count
    -l : line count

38. cat > file (make a new file with some words)
    ^D : ctrl + D, exit

39. cat >> file (append standard output to a file)

40. cat file1 file2 > file3 (concatenate file1 file2 to a new file3)

41. sort < file (output the sorted file content)

42. sort < file1 > file2 (redirect the sorted content of file1 to file2)

43. who (list users currently logged in)
    who > names.txt

44. who | sort
    command1 | command 2 (pipe the output of command1 to the input of command2)
    equals to:
    who > name.txt
    sort < name.txt
    delete name.txt

45. • (wildcard)
      The character * is called a wildcard, and will match against none or more character(s) in a file (or directory) name.
      ls list*

46. ? (wildcard)
    The character ? will match exactly one character. So ?ouse will match files like house and mouse, but not grouse.

47. In naming files, characters with special meanings such as / * & % , should be avoided. Also, avoid using spaces within names. The safest way to name a file is to use only alphanumeric characters, that is, letters and numbers, together with _ (underscore) and . (dot).

48. man <command> (online help)

49. whatis <command> (one line description of the command)

50. apropos <keyword> (match commands with keyword in their man pages)

. echo " "
-e : enable 转义字符
\a 警告 (bell)
\b 退格
\c 禁用拖尾换行（与 -n 选项作用相同）
\f 换页（在视频显示中清空屏幕）
\n 换行
\r 回车
\t 水平制表符