Using the Windows Linux Subsystem - Storming …Installing the Windows Linux Subsystem 1. Run the...

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Using the Windows Linux Subsystem

last update: June 10th, 2020

Table of Contents

Installing the Windows Linux Subsystem................................................................................................................ 3

Potential issues on conflicts in C/C++ installation: ......................................................................................... 8

Install a programming editor .............................................................................................................................. 9

Compiling and linking without using an IDE ........................................................................................................ 10

Sample codes ................................................................................................................................................ 10

how to build (compile + link + execute) ............................................................................................................ 10

The three most basic compiler options you should know: ........................................................................... 11

Basic linux commands you should know .............................................................................................................. 13

Linux Commands Exercises ................................................................................................................................... 18

Part I ................................................................................................................................................................. 18

Simple standard output ............................................................................................................................. 18

File paths and folder navigation ............................................................................................................... 18

Permissions ................................................................................................................................................. 19

Process Information ................................................................................................................................... 19

Searching..................................................................................................................................................... 19

Part II ................................................................................................................................................................ 20

Sample Scripting ................................................................................................................................................... 21

Show how to do factorial of a number using “while” .................................................................................. 21

Show how to do factorial of a number using “for” ....................................................................................... 21

Automate a test with usaco’s #.in test files .................................................................................................. 21

Read one line at a time from a file. .............................................................................................................. 21

Function Script Samples ............................................................................................................................... 23



Installing the Windows Linux Subsystem

1. Run the PowerShell as an Administrator

a. Type in powershell in the Search window

b. Right mouse click Windows PowerShell and click “Run as administrator”

2. In the PowerShell window type the command:

Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux



You will then see this…

3. Reboot your machine

4. Install Linux

a. Run Microsoft Store

b. Type linux in the search window

c. Select Ubuntu

d. Click Install

e. When finished click Launch

f. You will need to wait a few minutes as the installation completes

Here are some screenshots:



5. Create user

a. You will be prompted for a username and password

b. Don’t forget your password

Sample user name … DO NOT Use the same one… this is just a sample.



6. Update Linux

a. Type sudo apt update && sudo apt upgrade (or sudo apt-get …)

b. When prompted to continue, hit Y and enter.

You will see a lot of status display like this:

7. Install Compilers

a. Type sudo apt install gcc

b. When prompted to continue, hit Y and enter.

c. Type “ sudo apt install g++”

d. When prompted to continue, hit Y and enter.

$ sudo apt install gcc

$ sudo apt install g++



8. Test compiler installation

a. Use the default editor “nano” to create a sample code, such as: main.cpp. At complete

b. Test it out with some simple sample code, such as this:

c. Hit ctrl-x to save and exit

d. Now type: g++ -lm -std=c++0x main.cpp -o main

e. It should have compiled ok. If so type in: ./main

9. You should be set up properly.

$ nano main.cpp

1. #include <iostream> 2. using namespace std; 3. 4. int main ( ) 5. { 6. int i; 7. cout << "Please enter an integer

value: ";

8. cin >> i; 9. cout << "The value you entered

is " << i;

10. cout << " and its double is

" << i*2 << ".\n";

11. return 0;

12. }



POTENTIAL ISSUES ON CONFLICTS IN C/C++ INSTALLATION:

Conflict in the g++ installation :

You need to rebuild the dependency :

If this still does not resolve the conflict, you may need to reinstall the following packets. However, do it one at

a time, and watch for messages…

There may be time when it told you to do the following, do it as instructed:

$ sudo apt-get install libgmpv4-dev

$ sudo apt-get install g++

sudo apt-get install gcc-5-multilib

sudo apt-get install lib32gcc1

sudo apt-get install libx32gcc1

sudo apt-get install gcc-5

sudo apt-get install libx32gcc-5-dev

$ sudo apt autoremove



INSTALL A PROGRAMMING EDITOR

There are quite a few programming editors available. Here lists 3 commonly used ones. To install : “sudo apt-

get update” before installing another package

1) Nano

⎯ Light weight text editor, but the most primitive one. Just run it from the shell command

window.

⎯ Pretty easy to navigate, nothing fancy though. No plug-ins features, but may utilize its

configuration file to customize somewhat.

⎯ Should come pre-installed.

2) Kate

⎯ This is a hefty graphical editor. Will need to run a graphical terminal windows in order to run

this. Cannot run this in the simple command shell window.

⎯ Some find it much more intuitive to navigate. Some plug-ins.

⎯ Need to install yourself : “ sudo apt-get install kate “

3) VIM

⎯ This is a light weight editor. Can run this in the simple command shell window.

⎯ Some find it difficult to navigate. Many plug-ins available, more flexible than Kate. Based on

SLANT community , Vim is ranked 1st. It is a lighter weight and fast editor.

⎯ Mostly come pre-installed, but you may need to install the plugins for some advanced features.

“…Vim is a powerful, portable, keyboard based text editor. Being text-based, vim is lightning fast,

with an incredible set of features developed over its multi decade existence….” By SLANT.

I highly recommend to learn how to use VI.

Reference this packet to have a crash course using VI.

Concise lookup sheet:

- https://www.cheatography.com/typo209/cheat-sheets/comprehensive-vim-cheat-sheet/pdf

- http://www.nathael.org/Data/vi-vim-cheat-sheet.svg

Interactive vi Editor Tutorial: Here you can practice Vim with context-aware help menu

You may want to customize color right at the beginning. Here is how:

➢ Look up available default color scheme from /usr/share/vim/vim74/colors/

➢ Edit .vimrc

➢ E.g. to add murphy scheme, add “color murphy” into the .vimrc

https://www.slant.co/

https://www.stormingrobots.com/prod/tutorial/pi/pi.pdf

https://www.cheatography.com/typo209/cheat-sheets/comprehensive-vim-cheat-sheet/pdf

http://www.openvim.com/sandbox.html



Compiling and linking without using an IDE

SAMPLE CODES

HOW TO BUILD (COMPILE + LINK + EXECUTE)

1) How to build (Compile and link) a single executable out of several files

13. //main.cpp --------------------

---------

14. #include <stdio.h>

15. #include <myH1.h>


17.

18. int main ()

19. {

20. ... write the code to test

the functions..

21. e.g.

22. cout << "Enter number

to find fib: ";

23. cin >> num;

24. cout << fib(num) <<

endl;

25. }

26. // <myH1.h>

27.

28. int fact (int i);

29. int fib (int);

30.

31. // <myH2.h>

32.

33. int gcd (int, int);

34.

35. // myFuncs2.cpp -----

--------

36. #include <iostream>

37. using namespace std;



40.

41. int gcd(int a, int b)

42. {

43. …

44. }

45. //myFuncs1.cpp ------

-------

46. #include <iostream>

47. using namespace std;


49. #include <stdlib.h>

50. #include <string.h>


52.

53. int fact(int i)

54. {

55. …

56. }

57.

58. int fib(int order) {

59. …

60. }



2) How to build a static library file (*.a) out of several files (no main() ) , then link the static library *.a

file(s) with your main file (the one with main() ) .

3) How to build a shared library file (*.so) out of several files (no main() ) , then link the shared library

*.so file(s) with your main file (the one with main() ) .

THE THREE MOST BASIC COMPILER OPTIONS YOU SHOULD KNOW :

-I: (upper case i) include path for header files -l : (lower case of ‘L’) -L : Library path -D : Preprocessor macro

Compile and link a single executable out of several files. Note the main.cpp is the only file containing the

function main()

1. g++ -Wall main.cpp myFuncs1.cpp myFuncs2.cpp -I./ -o runThis 2.

Build a static library file (*.a) out of several files (no main() ) , then link the static library *.a file(s) with your

main file (the one with main() ) .

3. g++ -Wall -c myFuncs1.cpp myFuncs2.cpp -I./ 4. ar -cvq libSample.a myFuncs1.o myFuncs2.c 5. ar -t libSample.a 6. g++ -Wall main.cpp -L./ -lSample -I./ -o runThis2 7.

How to build a shared library file (*.so) out of several files (no main() ) , then link the shared library *.so file(s)

with your main file (the one with main() ) .

Do note : “-I” (this lower case of ‘L’) .

8. g++ -Wall -c -fPIC myFuncs1.cpp myFuncs2.cpp -I./ 9. g++ -shared -o libmySample.so myFuncs1.o myFuncs2.o 10.

11. g++ -Wall main.cpp -L./ -lmySample -I./ -o runThis3

12.

Note that the “-L./” and “-I./” (this lower case of ‘L’) indicates the path where the build will find the library

file and header file respectively.



May use LD_LIBRARY_PATH to add in customize library path, C_INCLUDE_PATH to add in customized include

path.

13.

14. export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:./ # if your *.so file is

in ./

15. export C_INCLUDE_PATH=$C_INCLUDE_PATH:./ # if your *.h files

are in ./

16.

17. g++ -Wall main.cpp -lmyFuncs -o runThis3 # do not need -L , -I

To demonstrate how the “-D” commonly being used:

18. g++ -Wall main.cpp myFuncs1.cpp myFuncs2.cpp -I./ -o runThis -D_SR_

19.

20. ./runThis

21.

Try this, and observe the difference from build it without -D_SR_

Reference (for windows OS instead):

⎯ Setting the Path and Environment Variables for Command-Line Builds ⎯ Walkthrough: Compiling a C Program on the Command Line

https://msdn.microsoft.com/en-us/library/f2ccy3wt.aspx

https://msdn.microsoft.com/en-us/library/bb384838.aspx



Basic linux commands you should know

Here is a very small set of commands that you should know. Try them out and observe what it does.

To look up full description of a command, use “man”, e.g. man ls

To look up a concise one-line manual page descriptions, use “whatis”, e.g. whatis ls

The ~50s linux commands that you should know as a software developer on Linux platform...

Files/ Folders

cat : concatenate files and print on the standard output

cd : (built-in) change directory or folder.

cmp : compare two files byte by byte

cp : copy files and directories

diff : compare files line by line

dir : list directory contents

ln : make links between files

ls : list directory contents

mkdir : create a directory

more : file perusal filter for crt viewing

mount : mount a filesystem

mv : move (rename) files

rm : remove files or directories

touch : change file timestamps

wc : print newline, word, and byte counts for each file

Search and Regular Expression

find : search for files in a directory hierarchy

grep : print lines matching a pattern

locate : find files by name

sed : stream editor for filtering and transforming text

sort : sort lines of text files

which : locate a command

system command (handle with care)

shutdown (built in) system shutdown

Security

chmod : change permissions of a file

chown : change ownership of a file

pwd : print name of current/working directory

sudo : execute a command as another user



Editing

nano : Nano's ANOther editor, an enhanced free Pico clone

vim : Vi IMproved, a programmers text editor

kate : Advanced text editor for KDE

Console display

clear : clear the terminal screen

echo : display a line of text

head : output the first part of files

more : file perusal filter for crt viewing

tail : output the last part of files

System utilities

alias : (built-in) set up alias for any commands

date : print or set the system date and time

export : export an environment variables and their values to all child (subsequent) processes.

man : an interface to the on-line reference manuals

uname : get name and information about current kernel

whoami : current user

history : GNU History Library

lscpu : display information about the CPU architecture

set : set environment variables

About the disk space

df : report file system disk space usage

du : estimate file space usage

Networking

ifconfig : (built-in) network configuration

ssh : OpenSSH SSH client (remote login program)

traceroute : (built-in) display the network route to a remote node

Package / Download

sudo apt-get : APT package handling utility : : command-line interface

wget : The non-interactive network downloader.

curl : transfer a file from a remote site.

Process info

htop : interactive process viewer

kill : send a signal to a process

ps : report a snapshot of the current processes.



top : display Linux processes

time : run programs and summarize system resource usage

uptime : Tell how long the system has been running.

watch : execute a program periodically, showing output fullscreen

Jobs

bg (built-in) move your process to the background

fg (built-in) move your process to the foreground

Ctrl+Z (built-in) suspend a process

misc

./ from current folder

../ one branch up : parent folder. ../../ == two branches up, etc.

!! Repeat the last command

useless but fun (you ma need to run sudo apt-get to install)

cal : displays a calendar and the date of Easter

banner : print large banner

fortune : print a random, hopefully interesting, adage

Try them out ***(Observe the behavior after each command. Be Inquisitive)

1. ls # l = lower case of L 2. man ls 3. cd / 4. pwd 5. cd ~/; pwd 6. mkdir playDir; pwd 7. cd playDir 8. ls -l # -l = lower case of L

9. ls -la 10. ls -ltra

11. cd ..

12. cd /mnt/c # This is your C Drive. Be curious! Check out the

sub-folders...

13. ls -l

14. ls -ltRa | more # this is LONG! So do “Ctrl-C” at any time to get

out

15. cd ~/; pwd

16. ls -l

17. mv playDir play

18. ls -l

19. echo “This is the 1st line.” > test1.txt

20. echo “This is the 2nd line.” >> test1.txt

21. cat test1.txt

22. echo “This is a hidden file.” > .test2.txt

23. ls -ltra > test1.txt

24. ls -l | wc -l >> test1.txt



25. echo “This is the end \! ” >> test1.txt

26. cat test1.txt

27. grep “this is” test1.txt

28. grep -i “this is” test1.txt

29. cd ~

30. pwd

31. clear

32. ls -lr # -l = lower case of L

33. dir -lr

34. ls -lR

35. dir -lR

36. ls -l | grep "^\.” # list all hidden files and directories

37. ls -l | grep “^d” # list sub-directories

38. ls -ltR | grep “^d”

39. ls -l | wc -l # count of nodes (files, directories, links,

etc.)

40. ls -lR | grep "^d”

41. alias ldir=’ls -lR | grep "^d"’ #you just created a new command!

42. ldir

43. clear

44. date

45. date +%D

46. date +"%T"

47. time

48. man -? > help.txt

49. tail -f help.txt

50. ls /root/

51. sudo ls /root/

52. wget https://www.stormingrobots.com/prod/pdf/csSyllabus.pdf &

53. du

54. du -sh

55. du -h * -d 1

56. du – h * -d 3

57. du -h * | sort -n # show and sort files by disk space usage size

58. du -h * | sort -nr

59. du -a . | sort -nr | head

60. du -a . | sort -nr | tail

61. df

62. df -h

63. df /home

64. echo "echo \"Hello World \" " > test.sh

65. cat test.sh

66. ls -l test.sh # you see: -rw-r--r-: 1 … test.sh

67. ./test.sh # fail to run

68. chmod +x test.sh

69. ls -l test.sh # you see: -rwxr-xr-x 1 … test.sh

70. ./test.sh

71. ps -ef

72. watch -n 1 "ps -ef" &

73. ps # find the PID (process ID) for this watch command

74. kill 3000 # replace 3000 with the PID of the “watch”

process

75. ps # now you see the process is gone

76. clear

77. history

78. !!

& == runs in background

http://www.stormingrobots.com/prod/pdf/AlgmCSyllabus.pdf



79. !w

Find a number corresponding to one of the previous commands. E.g. one of them is 50:

80. !50 # if 50 exists in your history commands list

81. top

82. Ctrl+Z # this suspend the process “top”

83. jobs # find the job # , e.g. [9]

84. fg 9 # type the # 9 from, the previous finding

85. bg 9 # put back to the background .

Now, you should try to find the process and kill it…

86. find . -name test.sh # locate test.sh from all sub-folders under

current dir

87. find . -print | grep -i lx # only list those files with “lx”

88. uptime

89. lscpu

90. ps ahuxf | sort | head -5 # short top 5 cpu usage processes

91. htop # show processes with top cpu usage ; you may need to

install it first

92. curl -O http://www.stormingrobots.com/prod/pdf/cs-syllabus.pdf

/mnt/c/your folder name here/Downloads/

93. ls -lt # check to see if you have downloaded cs-syllabus.pdf

94.

About redirection ( > )

95. echo Hello World 1. > test.txt

96. echo cat test.txt

97. echo Hello World 2. >> test.txt

98. echo cat test.txt

99. echo “hello” 1>/dev/null # suppress the standard output

Wish to redirect standout to a file:

⎯ runYourCommand &> file == redirect all the standard output (stdout, such as printf..) and

standard error (stderr, such as fprintf(stderr,... ) from your command to a file

Now, your history table should be very long.. Clear it up:

100. history -c

http://www.stormingrobots.com/prod/pdf/cs-syllabus.pdf



Linux Commands Exercises

PART I

1. Change your password. Logout and log back in. (don’t forget.. it will be multiple nuisance steps to do if

you lost it. ) 2. Change it back to what it was before.

S IMPLE STANDARD OUTPUT

1. Enter a command to print "Hello world" on the screen. 2. Display the current date and time on the screen.

F ILE PATHS AND FOLDER NAVIGATION

1. Display the full path of your home folder. 2. Go to your own windows user folder. Hint /mnt/c . 3. List all the files in your current folder. 4. List all the sub-directories and files in your current folder. 5. Go back to your linux home folder. (do it without typing full path) 6. Display the full path of current folder. 7. Create two new folders called “temp1” and “temp2”. 8. Create a file with content “hello world 1’ as temp1.txt under “temp1”. BUT, do that without going into temp1

folder. 9. Create a file with content “hello world 2’ as temp2.txt under “temp2”. BUT, do that without going into temp2

folder. 10. Take a look what is in the temp1, and temp2 folder 11. Copy the temp1.txt into ‘temp2” folder. 12. Take a look what is in the temp2 folder 13. List all the files in this folder. Use a more detailed listing where you can see the files' permissions, date written,

etc. 14. Change the time stamp for both files under temp1 and temp2. 15. List all the files in this folder. Use a more detailed listing where you can see the files' permissions, date written,

etc. 16. Go into temp1 folder, and create another called temp1_2., then go into this folder temp1_2. 17. Copy the file from temp2 into this new temp1_2 folder. 18. List all files to check that out to see the copy was successful. 19. Compare the file in temp1_2 against the temp2.txt in temp2 folder to ensure they are the same. 20. Go back home folder. 21. Capture the current full path (recursively) into a file called allMyTempfolders.txt. 22. Search recursively for any file with “temp in its file name. 23. Delete temp1 folder with a single command. (The command you use should also delete all of the files inside of

the folder.) 24. Rename temp2 folder to testDir. 25. Show the current path.



26. Clear the screen 27. Capture all the commands into a file called hw1.txt 28. Edit this hw1.txt to leave only the commands equivalent to this set of exercises. That means, remove all those

commands which do not apply. Therefore, there should be only 27 lines left in your hw1.txt file.

PERMISSIONS

1. Clear the history 2. Go to “testDir”, create a file called 'testFile' containing the text “It's a secret!” using the echo command. 3. Check out what is in your current folder using “ls”. 4. Do something to make this file hidden from the simple “ls” command. 5. Check out what is in your current folder using “ls” again. Can you see the test File that you just created? 6. Try to display the content of this test File using cat. What happen?

7. Change the permission of this file to non-readable. 8. Try to display the content of test File using cat. What happen?

9. Change the permission of this file to readable, but not writable. 10. Try to display the content of test File using cat.

11. Try to attach more content to the end of the file. What happen? 12. Delete this test file. 13. Capture all the commands into a file called hw2.txt 14. Edit this hw2.txt to leave only the commands equivalent to this set of exercises. That means, remove all those

commands which do not apply. Therefore, there should be only 12 lines left in your hw2.txt file.

PROCESS INFORMATION

1. Clear the past history 2. Enter a command to display the version of the Linux kernel that you are you using. 3. List all of the processes that are currently running. (with e a ) 4. Show the top linux processes 5. interactive linux process viewer 6. suspend (4) process 7. type “sleep 1000 &” 8. type “sleep 2000 &” 9. display the jobs which have been suspended 10. Display the process table in tree format 11. kill all these 3 processes.

SEARCHING

1. Use grep to display the entry with your username in the file '/etc/passwd'. 2. Capture all the commands into a file called hw3.txt 3. Edit this hw3.txt to leave only the commands equivalent to the set of exercises. That means, remove all those

commands which do not apply. Therefore, there should be only 13 lines left in your hw3.txt file. Go to next page ...



PART II

(credit: University of Washington – School of Computer Science and Engineering)

Use a text editor (nano or vi) to create a plain text file named hw4.txt containing answers to the following

questions:

1. Use the man pages to find out what wc does. Give a brief description of it here. What does the -l option for wc do?

2. Run wc on the folder '/etc/passwd' and copy and paste your findings. 3. What command would you use to a terminate (stop) a process? 4. What information does the environment variable $HOME store? (Hint: use 'echo $HOME' to investigate.) 5. List two other important environment variables on your computer and what they store. Why are these variables

important? 6. If you created a file 'bigredbutton' somewhere on your computer and couldn't remember what folder it was in,

what command could you use to find it? Just give the name of the command. You do not need to describe all of the necessary arguments.

7. How is the command in the answer to the previous question different from the 'which' command? 8. How does the command “echo Hello World! > something” differ from “echo Hello World!”? 9. Assume we have run the first echo command from the previous question and now we execute “echo more text

> something”. Describe what this does. 10. Now assume we have run the commands in the previous two questions and now we execute “echo yet more

text >> something”. Describe what this does.



Sample Scripting

Note: should always start the script with “#!/bin/bash”

SHOW HOW TO DO FACTORIAL OF A NUMBER USING “WHILE”

101. echo "do Fact ... "

102. echo "Enter a number: "

103. read num

104. fact=1

105.

106. echo "get Factorial($num) with while" #--------------------------------

----------

107. while [ $num -gt 1 ]

108. do

109. fact=$((fact * num))

110. num=$((num : 1))

111. done

112. echo $fact

SHOW HOW TO DO FACTORIAL OF A NUMBER USING “FOR”

113. for ((i=2; i<=num;i++)) {

114. fact=$((fact * i))

115. }

AUTOMATE A TEST WITH USACO’S #.IN TEST FILES

116. printf "runThis.sh <exeName> <max # test>...\n\n "

117. read exeName num

118. let i=1

119. while [ $((i)) -le $num ]

120. do

121. printf "test $i.in...\n"

122. cp $i.in $exeName.in

123. diff $i.out $exeName.out

124. i=$((i+1))

125. done

READ ONE LINE AT A TIME FROM A FILE.

126. #!/bin/bash

127.

128. echo "display the whole file-------"

129. cat file.txt

130.



131. echo "display whole file without linebreak------"

132. echo $(cat file.txt)

133.

134.

135. echo "display each word-------: "

136. for word in $(cat file.txt)

137. do

138. echo "$word"

139. done

140.

141. echo "display each line------: "

142. old_IFS=$IFS

143. IFS=$'\n' # new field separator

144.

145. for line in $(cat file.txt)

146. do

147. echo ":: $line"

148. done

149. IFS=$old_IFS

150.

151. echo "display each line use file redirect ------: "

152. while read line

153. do

154. echo -e ">> $line \n"

155. done < file.txt



FUNCTION SCRIPT SAMPLES

The following samples show how to read a number from a file.

Sample 1: passing in a string argument

61. doFact()

62. {

63. fname=$1

64. fact=1

65. echo "Read from file: $fname"

66.

67. read num < $1

68. # or

69. # num=$(cat $fname)

70.

71. echo "got $num"

72. for ((i=2; i<=num;i++))

73. {

74. fact=$((fact * i))

75. }

76. echo "$num! = $fact"

77. }

78.

79. doFact "1.in"



Sample2: passing in 2 arguments

More reference: Learn more on important Linux commands.

80. doFact()

81. {

82. num=$1

83. fact=1

84. echo "Read from file: $2"

85.

86. if [[ $2 = 1 ]]

87. then

88. echo "do while ... "

89. echo "get Factorial($num) with while"

90. while [ $num -gt 1 ]

91. do

92. fact=$((fact * num))

93. num=$((num - 1))

94. done

95. echo $fact

96.

97. else

98. echo "do for ... "

99. echo "get Factorial($num) with for"

100. for ((i=2; i<=num;i++))

101. {

102. fact=$((fact * i))

103. }

104. echo $fact

105. fi

106. }

107.

108. echo -e "do Factorial ...: e.g.\n func.sh (do

factorial using for)"

109. echo -e "\n func.sh 1 (do factorial using

while)\n\n"

110.

111. echo "Enter a number: "

112. read num

113. doFact $num "file.txt"

https://www.stormingrobots.com/prod/tutorial/pi/PI-Exercises.pdf

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