startlearning

#!/usr/bin/env bash

#uncomment the following command for debug mode
#set -x

#<---arguments-input-defined--->
args="$@"
comand="startlearning ${args}"
PWD=$(pwd)
#<<<----------colour substitution by variables---------->>>
B0="$(printf '\033[100m')" S0="$(printf '\033[30m')"
B1="$(printf '\033[91m')" S1="$(printf '\033[31m')"
B2="$(printf '\033[92m')" S2="$(printf '\033[32m')"
B3="$(printf '\033[93m')" S3="$(printf '\033[33m')"
B4="$(printf '\033[94m')" S4="$(printf '\033[34m')"
B5="$(printf '\033[95m')" S5="$(printf '\033[35m')"
B6="$(printf '\033[96m')" S6="$(printf '\033[36m')"
B7="$(printf '\033[97m')" S7="$(printf '\033[37m')"
R1="$(printf '\033[0;1m')" R0="$(printf '\033[00m')"
#<<<-----------special colours----------->>>
T="$(printf '\033[5;1;32m')"
#<<<----------Variables declaration---------->>>
OS=$(uname -o)
distro=$(pwd)
exit_on_signal_SIGINT () {
    echo "${S1} [✗] Received INTR call - Exiting...${R0}"
#    exit 0
return 1
}
trap exit_on_signal_SIGINT SIGINT
#<<<----------Requirements---------->>>
case ${OS} in
    Android)
	pkg=(python pv sox)
	for i in "${pkg[@]}"
	do
	    sleep 0.3
	    if ! hash "${i}" 2>/dev/null;then
		echo -e "${R1}Installing ${i}"
		pkg install "${i}" -y
	    fi
	done
	;;
    GNU/Linux)
	pkg=(pv sox)
	os="$(source /etc/os-release && echo "${ID}" )"
	case "${os}" in
	    arch|archarm|arcolinux|artix|manjaro|garuda|predator|endeavouros)
		pm="sudo pacman -Syu --noconfirm"
		;;
	    debian|ubuntu|linuxmint|kali|parrot|raspbian)
		pm="sudo apt install -y"
		;;
	    fedora)
		pm="sudo dnf install -y"
		;;
	    freebsd)
		pm="sudo pkg install -y"
		;;
	    gentoo)
		pm="sudo emerge --ask"
		;;
	    void)
		pm="sudo xbps-install"
		;;
	    puppy_fossapup64)
		pm="sudo pkg g"
		;;
	    nixos)
		pm="nix-env -iA nixos."
		;;
	    solus)
		pm="eopkg install -y"
		;;
	    *)
		echo -e $RED "Sorry... this is sadly not a supported distro!"
		exit 0
		;;
	esac
	for i in "${pkg[@]}"
	do
	    sleep 0.3
	    if ! hash "${i}" 2>/dev/null;then
		echo -e "${R1}Installing ${i}"
		${pm} "${i}"
	    fi
	done
	! hash python3 && echo "install python and install lolcat from pip."
	;;
    *)
        printf "${S2}[${S1}!${S2}]${S1} Unsupported operating system detected!!${R0}\n"
	exit 1
	;;
esac
echo
printf "${S5}Requirements installed!!${R0}\n" | pv -qL 100
echo
#<<<----some functions---->>>
wait() {
  sleep 0.02
}
__ENTER__() {
  echo
  printf "Press enter key to continue${T}__\e[0;0;0m"
  read ENTER
  echo
}
__chapter1__() {
printf "${S6}LETS START OUR BASH LEARNING ;)${R0}\n"
echo

echo -e "      ${B4} ${S2}CHAPTER:- 1 ${R0} ${R1}"
echo
echo -e "
Bash is an acronym of “Bourne-Again Shell”. It is a
default command-line interpreter for UNIX and Linux
based operating systems. In UNIX and Linux based operating
systems, a terminal window is consist of a shell and Bash.
" | pv -qL 1000 | lolcat
play assets/chapter_1/ch_1pr_1.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
first of all we will learn basic commands! so lets go...
" | pv -qL 1000 | lolcat
echo -e "
First command is 'echo' or 'printf'

We use any of these to command to print anything on the screen.
examples:-

" | pv -qL 1000 | lolcat
echo '#1) echo "hello world"' | pv -qL 1000 | lolcat

echo -e "
result==> hello world
" | pv -qL 1000 | lolcat
echo '#2) printf "hello world\n"' | pv -qL 1000 | lolcat

echo -e "
result==> hello world
" | pv -qL 1000 | lolcat
echo '# note in printf we used (\n) to go to next line so that other next objects must be printed on next line! but in echo we do not need to do so.' | pv -qL 1000 | lolcat
play assets/chapter_1/ch_1pr_2.mp3 > /dev/null 2>&1
__ENTER__

echo -e "
if you want to make a script for printing your desired thing, then lets have an example for that!! ;)

  first of all you have to open any text editor for example :- 'nano', 'vim', 'neovim', etc.

  since you are a beginer then you must try with nano;
  choose a name for your script (say, test1)

then open nano by 'nano test1'

  here you have to define the language which you are going to write (here its 'bash')

  in first line have to write '#!/bin/bash'

  you may noticing '#!' that what is this?!!

  => '#!' is called shebang. In computing, a shebang is the character sequence consisting of the characters number sign and exclamation mark at the beginning of a script. It is also called sha-bang, hashbang, pound-bang, or hash-pling.
" | pv -qL 1000 | lolcat
play assets/chapter_1/ch_1pr_3.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
After this from second line you can write your codes ;)

example:-
#!/bin/bash
echo \"hello world\"
echo  #<- this blank echo is used to make one line gap!" | pv -qL 1000 | lolcat
echo 'printf "hello world\n"' | pv -qL 1000 | lolcat
echo -e "

#After writing all your codes you need to save then!
command to save :- CTRL + X
 then it will ask you if you want to save or not, just press y and then Enter key!

NOW, in order to run it you have to give it execution permission by:- chmod +x test1

of your script name is different then you just have to replace test1 by your script name! :)

now it time to run it!!

you have two ways to run it :-

1>     ./test1
2>     bash test1

then it will run your script :)
" | pv -qL 1000 | lolcat
play assets/chapter_1/ch_1pr_4.mp3 > /dev/null 2>&1
echo -e "
result:-
hello world
              <----there is a gap because be have used a blank echo in our script
hello world
" | pv -qL 1000 | lolcat
play assets/chapter_1/ch_1pr_5.mp3 > /dev/null 2>&1
__ENTER__
}

__chapter2__() {
echo -e "      ${B4} ${S2}CHAPTER:- 2 ${R0} ${R1}"
echo
echo -e "
    In the previous chapter we have leant how to make a simple bash script.
      Now its time to learn some more basic commands or syntaxes to use in our
      script to make it awesome :)!
" | pv -qL 1000 | lolcat
play assets/chapter_2/ch_2pr_1.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
  Quick note: Anything encased in [ ] means that it’s optional.
              Some commands can be used without options or specifying files.

 ls — List directory contents

	ls is probably the most common command.
	A lot of times, you’ll be working in a directory
	and you’ll need to know what files are located there.
	The ls command allows you to quickly view all files
	within the specified directory.

Syntax: ls [option(s)] [file(s)]

Common options: -a, -l
" | pv -qL 1000 | lolcat
play assets/chapter_2/ch_2pr_2.mp3 > /dev/null 2>&1
__ENTER__
echo -e "

 echo — Prints text to the terminal window

       echo prints text to the terminal window and is
       typically used in shell scripts and batch files
       to output status text to the screen or a computer file.
       Echo is also particularly useful for showing the values of
       environmental variables, which tell the shell how to behave
       as a user works at the command line or in scripts.

Syntax: echo [option(s)] [string(s)]

Common options: -e, -n
" | pv -qL 1000 | lolcat
play assets/chapter_2/ch_2pr_3.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 touch — Creates a file

       touch is going to be the easiest way to create new files,
       but it can also be used to change timestamps on files and/or directories.
       You can create as many files as you want in a single command without worrying
       about overwriting files with the same name.

Syntax: touch [option(s)] file_name(s)

Common options: -a, -m, -r, -d

#To create multiple files:-

example:-
    touch test1 test2 test3 test4
result :- it will create all files that you supposed
to be created. i.e test1, test2, test3, test4

" | pv -qL 1000 | lolcat
play assets/chapter_2/ch_2pr_4.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 mkdir — Create a directory

       mkdir is a useful command you can use to create directories.
       Any number of directories can be created simultaneously which
       can greatly speed up the process.

Syntax: mkdir [option(s)] directory_name(s)

Common options: -m, -p, -v

#To create directories under directry

example:-
    mkdir -p test/test1/test2/test3
result :- it has created a directory named test3 inside
test2 which is inside test1 which is also inside the test directory
" | pv -qL 1000 | lolcat
play assets/chapter_2/ch_2pr_5.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 grep — search

       grep is used to search text for patterns specified by the user.
       It is one of the most useful and powerful commands. There are
       often scenarios where you’ll be tasked to find a particular string
       or pattern within a file, but you don’t know where to start looking,
       that is where grep is extremely useful.

Syntax: grep [option(s)] pattern [file(s)]

Common options: -i, -c, -n , -o
example:-
    uname -o | grep 'Android'
result:- Android   #for android users
result:-           #for other users its vacant or we can say null.

" | pv -qL 1000 | lolcat
play assets/chapter_2/ch_2pr_6.mp3 > /dev/null 2>&1
__ENTER__
}

__chapter3__() {
echo -e "      ${B4} ${S2}CHAPTER:- 3 ${R0} ${R1}"
echo
echo -e "
      ${S6}In this chapter we will learn our next basic command. So let's start!!${R0}
" | pv -qL 1000
play assets/chapter_3/ch_3pr_1.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 man — Print manual or get help for a command

       The man command is your manual and is very useful when you
       need to figure out what a command does. For example, if you
       didn’t know what the command rmdir does, you could use the
       man command to find that out.

Syntax: man [option(s)] keyword(s)

Common options: -w, -f, -b
" | pv -qL 1000 | lolcat
play assets/chapter_3/ch_3pr_2.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 cd — Change directory

      cd will change the directory you’re in so that you can get
      info, manipulate, read, etc. the different files and
      directories in your system.

Syntax: cd directory
" | pv -qL 1000 | lolcat
play assets/chapter_3/ch_3pr_3.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 pwd — Print working directory

       pwd is used to print the current directory you’re in.
       As an example, if you have multiple terminals going and
       you need to remember the exact directory you’re working
       within, then pwd will tell you.

Syntax: pwd
  example :- pwd       #in home directory of termux

result:- /data/data/com.termux/files/home

" | pv -qL 1000 | lolcat
play assets/chapter_3/ch_3pr_4.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 mv — Move or rename directory

      mv is used to move or rename directories. Without
      this command, you would have to individually rename
      each file which is tedious. mv allows you to do batch
      file renaming which can save you loads of time.

Syntax: mv [option(s)] argument(s)

Common options: -i, -b, -v

example:- to move file from curren directory to home directory

      mv -v test \$HOME  #\$HOME is path of home directory

example:- to rename a file

      mv test test1

" | pv -qL 1000 | lolcat
play assets/chapter_3/ch_3pr_5.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 rmdir — Remove directory

         rmdir will remove empty directories. This can help clean
         up space on your computer and keep files and folders organized.
         It’s important to note that there are two ways to remove
         directories: rm and rmdir.
         The distinction between the two is that rmdir will only
         delete empty directories, whereas rm will remove directories and
         files regardless if they contain data or not.

Syntax: rmdir [option(s)] directory_names
     or rm    [option(s)] directory or file name
Common options: -p, -f, -rf
example:- rmdir test   #it will delete test directory if it is empty
          rm -rf test  #it will forcely delete the directory or
                        file whether it is empty or not
" | pv -qL 1000 | lolcat
play assets/chapter_3/ch_3pr_6.mp3 > /dev/null 2>&1
__ENTER__
}

__chapter4__() {
echo -e "      ${B4} ${S2}CHAPTER:- 4 ${R0} ${R1}"
echo
echo -e "
      ${S6}In this chapter we will learn some advanced command. So let's start!!${R0}
" | pv -qL 1000
play assets/chapter_4/ch_4pr_1.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 locate — Locate a specific file or directory

          This is by far the simplest way to find a file or directory.
          You can keep your search broad if you don’t know what exactly it is
          you’re looking for, or you can narrow the scope by using wildcards
          or regular expressions.

Syntax: locate [option(s)] file_name(s)

Common options: -q, -n, -i

Exit Status: This command will exit with status 0 if any specified match found.
             If no match founds or a fatal error encountered, then it will exit with
             status 1. In future chapters we will learn how to use these exit status for
             doing proper thing in a script. Till then just remember that, if, any command
              runs successfully then it will exit with status 0.
" | pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_2.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 less — view the contents of a text file

        The less command allows you to view files without opening an editor.
        It’s faster to use, and there’s no chance of you inadvertently
        modifying the file.

Syntax: less file_name

Common options: -e, -f, -n

To exit less just press these keys combination:- 'esc' + ':' + 'q'

" | pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_3.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 compgen — Shows all available commands, aliases, and functions

           compgen is a handy command when you need to reference all
           available commands, aliases, and functions.

Syntax: compgen [option(s)]

Common options: -a, -c, -d
" | pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_4.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 > — redirect stdout

     The > character is the redirect operator. This takes the output
     from the preceding command that you’d normally see in the terminal
     and sends it to a file that you give it. As an example, take

     echo “contents of file1” > file1.

     Here it creates a file called file1 and puts the echoed string into it.
Note:- if you use this > character to put your objects in a particular file,
       it will erase the previously written things in that file if found something!!

       so, if you don't want to erase previous things just use > this character
       two times i.e >>

example:-
          echo \"my name is BHUTUU\" > test1

     result:- It will write 'my name is BHUTUU' in test1 file

 now let's write something more in the same file


         echo \"I love BHUTUU\" > test1

     result:- It will erase the previous line and write 'I love BHUTUU' in that file

 if we had done it in following after writing first line:-
         echo \"I love BHUTUU\" >> test1

     result:- It would have kept the previous line as usual and also write
              'I love BHUTUU' in the next line.


Syntax: >

Common options: n/a

" pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_5.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
 cat — Read a file, create a file, and concatenate files

       cat is one of the more versatile commands and serves three main
       functions: displaying them, combining copies of them, and
       creating new ones.

Syntax: cat [option(s)] [file_name(s)] [-] [file_name(s)]

Common options: -n, -E, -s, -v, -A

examples:-
#1) To view a single file:->

Command:- cat filename

Output:- It will show content of given filename

#2) To view multiple files:->

Command:- cat file1 file2

Output:- This will show the content of file1 and file2.

#3) To view contents of a file preceding with line numbers:->

Command:- cat -n filename

Output:- It will show content with line number

example:- cat -n  BHUTUU.txt
1)This is BHUTUU
2)A unique array

#4) Create a file:->

Command:- cat >newfile

Output:- Will create and a file named newfile
" | pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_6.1.mp3 > /dev/null 2>&1
__ENTER__

echo -e "
#5) Copy the contents of one file to another file:->

Command:- cat [filename-whose-contents-is-to-be-copied] > [destination-filename]

Output:- The content will be copied in destination file

#6) Cat command can suppress repeated empty lines in output:->

Command:- cat -s BHUTUU.txt

Output:- Will suppress repeated empty lines in output

#7) Cat command can append the contents of one file to the end of another file:->

Command:- cat file1 >> file2

Output:- Will append the contents of one file to the end of another file

#8) Cat command can display content in reverse order using tac command:->

Command:- tac filename

Output:- Will display content in reverse order

#9) Cat command can highlight the end of line:->

Command:- cat -E \"filename\"

Output:- Will highlight the end of line

#10) If you want to use the -v, -E and -T option together,
     then instead of writing -vET in the command, you can
     just use the -A command line option->

Command:- cat -A  \"filename\"

#11) Cat command to open dashed files:->


Command:- cat -- \"-dashfile\"

Output:- Will display the content of -dashfile

#12) Cat command if the file has a lot of content and can’t fit in the terminal:->

Command:-cat \"filename\" | more

Output:- Will show that much content, which could fit in terminal and will ask to show more.

#13) Cat command to merge the contents of multiple files:->

Command:- cat \"filename1\" \"filename2\" \"filename3\" > \"merged_filename\"

Output:- Will merge the contents of file in respective order and will insert that content in \"merged_filename\"

#14) Cat command to display the content of all text files in the folder:->

Command:-cat *.txt

Output:- Will show the content of all text files present in the folder.

#15) Cat command to write in an already existing file:->

Command:- cat >> BHUTUU.txt
          The newly added text.

Output:- Will append the text \"The newly added text.\" to the end of the file.
" | pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_6.2.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
Let's see one more example:-

cat <<- VAR > \${HOME}/BHUTUU.txt
hello my name is Suman kumar ~BHUTUU.
I love BHUTUU.
I love to make automation programs.
VAR


result:- It will write the following in BHUTUU.txt file in home directory:-
         hello my name is Suman kumar ~BHUTUU.
         I love BHUTUU.
         I love to make automation programs.

NOTE:-
      #you can use '>>' in place of '>' for declaring path and file name of the output
       as you already knew the diffrence between the result of '>' and '>>' .!

      #you can write any variable in place of 'VAR'. It is here used to set the
       starting and ending point of the objects to be written in the output file.
" | pv -qL 1000 | lolcat
play assets/chapter_4/ch_4pr_6.3.mp3 > /dev/null 2>&1
__ENTER__
}
__chapter5__() {
echo -e "      ${B4} ${S2}CHAPTER:- 5 ${R0} ${R1}"
echo
echo -e "
      In this chapter we are going to learn some more useful linux commands! so let's get  started
" | pv -qL 1000 | lolcat
play assets/chapter_5/ch_5pr_1.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
  | — Pipe

         A pipe takes the standard output of one command
         and passes it as the input to another.

Syntax: |

Common options: n/a

For example:-

   echo \"hello\" | grep -o \"o\"

   Result:- o
" | pv -qL 1000 | lolcat
play assets/chapter_5/ch_5pr_2.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
  head — Read the start of a file

         By default, the head command displays the first
         10 lines of a file. There are times when you may
         need to quickly look at a few lines in a file and
         head allows you to do that. A typical example of
         when you’d want to use head is when you need to
         analyze logs or text files that change frequently.

Syntax: head [option(s)] file(s)

Common options: -n
" | pv -qL 1000 | lolcat
play assets/chapter_5/ch_5pr_3.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
  tail — Read the end of a file

         By default, the tail command displays the last
         10 lines of a file. There are times when you may
         need to quickly look at a few lines in a file and
         tail allows you to do that. A typical example of
         when you’d want to use tail is when you need to
         analyze logs or text files that change frequently.

Syntax: tail [option(s)] file_names

Common options: -n
" | pv -qL 1000 | lolcat
play assets/chapter_5/ch_5pr_4.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
chmod — Sets the file permissions flag on a file or folder

         There are situations that you’ll come across where you
         or a colleague will try to upload a file or modify a
         document and you receive an error because you don’t
         have access. The quick fix for this is to use chmod.
         Permissions can be set with either alphanumeric characters
         (u, g, o) and can be assigned their access with w, r, x.
         Conversely, you can also use octal numbers (0-7) to change the
         permissions. For example, chmod 777 my_file will give access to
         everyone.

Syntax: chmod [option(s)] permissions file_name

Common options: -f, -v
" | pv -qL 1000 | lolcat
play assets/chapter_5/ch_5pr_5.mp3 > /dev/null 2>&1
__ENTER__
echo -e "
  exit — Exit out of a directory

         The exit command will close a terminal window, end the execution
         of a shell script, or log you out of an SSH remote access session.

Syntax: exit

Common options: n/a
" | pv -qL 1000 | lolcat
play assets/chapter_5/ch_5pr_6.mp3 > /dev/null 2>&1
__ENTER__
}













if [[ ${comand} == 'startlearning -2' ]]; then
chap=(2 3 4)
for i in ${chap[@]}; do
__chapter${i}__
done
elif [[ ${comand} == 'startlearning -3' ]]; then
chap=(3 4)
for i in ${chap[@]}; do
__chapter${i}__
done
elif [[ ${comand} == 'startlearning -4' ]]; then
chap=(4)
for i in ${chap[@]}; do
__chapter${i}__
done
elif [[ ${comand} == 'startlearning -5' ]]; then
chap=(5 6)
for i in ${chap[@]}; do
__chapter${i}__
done
#elif [[ ${comand} == 'startlearning -6' ]]; then
#chap=(6)
#for i in ${chap[@]}; do
#__chapter${i}__
#done

elif [[ ${comand} == 'startlearning -u' || ${comand} == 'startlearning --update' ]]; then
git pull
exit 1
elif [[ ${comand} == 'startlearning -h' || ${comand} == 'startlearning --help' ]]; then
printf "        \e[1;37m /\ .__    ._ _  _ .__|_ _._|_o _ ._  __ |_  _ |._  ._ _  _ ._     _\e[0m\n"
printf "        \e[1;33m/--\|(_||_|| | |(/_| ||_(_| |_|(_)| |    | |(/_||_) | | |(/_| ||_|(/_\e[0m\n"
printf "        \e[1;31m      _|                                        |\e[0m\n"

echo
echo -e "
${S5}<${S1}=========${S2}ARGUMENTS${S1}=======================${S2}USAGE${S1}=====================================${S5}>${R0}

       ${S6} -h ${S7}OR ${S6}--help               ${S4}To show this argumentation help menue${R0}

       ${S6} -u ${S7}OR ${S6}--update             ${S4}To update ! :)${R0}

       ${S6} -c ${S7}OR ${S6}--content            ${S4}To show the list of chapters in this program!${R0}
${S5}<${S1}----${S2}x${S1}----${S5}>${R0}

${S7}IF you want to open any particular chapter and continue from there then do:-${R0}

  ${S2} ./startlearning -chapeter_number${R0}

${S6}example:-${R0}

${S2}  ./startlearning -3${R0}
${S4}This will start from chapter 3 and continue${R0}

${S2}>>> ${S6}To run this program just run${R0} ${B5} './startlearning' ${R1}

${S5}<${S1}----${S2}x${S1}----${S5}>${R0}


${S3}To exit program just do ${S3}${B7} ctrl + c ${R1}

${S5}<${S1}----${S2}x${S1}----${S5}>${R0}
"
elif [[ ${comand} == 'startlearning -c' || ${comand} == 'startlearning --content' || ${comand} == 'startlearning --chapter' || ${comand} == 'startlearning --list' ]]; then
echo -e "

${B4}${T2}SL. NO${R0}${R1}               ${B4}${T2} Chapter Name and discription.${R0}${R1}

${S6}1.                    Introduction to bash scripting${R0}
                       ${S3} *definition of bash${R0}
                       ${S3} *Introduction to printing commands${R0}
                       ${S3} *Shebang (#!)${R0}
                       ${S3} *how to give exicution permission to any script${R0}
                       ${S3} *how to run a bash script${R0}

${S6}2.                    Introduction to basic commands${R0}
                       ${S3} *ls    -List directory contents${R0}
                       ${S3} *echo  -printing command${R0}
                       ${S3} *touch -file creating command${R0}
                       ${S3} *mkdir -directory creating command${R0}
                       ${S3} *grep  -search command${R0}

${S6}3.                    Basic commands part -2${R0}
                       ${S3} *man — Print manual or get help for a command${R0}
                       ${S3} *cd — Change directory${R0}
                       ${S3} *pwd — Print working directory${R0}
                       ${S3} *mv — Move or rename directory${R0}
                       ${S3} *rmdir — Remove directory${R0}

${S6}4.                    Introduction to some advanced commands${R0}
                       ${S3} *locate — Locate a specific file or directory${R0}
                       ${S3} *less — view the contents of a text file${R0}
                       ${S3} *compgen — Shows all available commands, aliases, and functions${R0}
                       ${S3} *> — redirect stdout${R0}
                       ${S3} *cat — Read a file, create a file, and concatenate files${R0}

${B3}${S5} This program is under development so expect some quirks! Other chapters will be added very soon !!${R0}${R1}

"
else
chap=(1 2 3 4)
for i in ${chap[@]}; do
__chapter${i}__
done
fi