Basics of Bash scripting
Bash aka (shell) is used mostly in the Unix and Linux systems this the commands we use Example ls list files in a directory or are mostly use cd changes the shells current working directory. Bash is great to write scripts with as it easy to learn and faster to script
so open your fav text editor and type the following line
the first line tells Unix that the file is to be executed by /bin/sh this the standard location of the shell on just about every Unix/Linux system this includes mac if you use termux #!/data/data/com.termux/files/usr/bin/bash
the next line type # my first script
the # symbol is use with out the ! as this marks the line as a comment and its ignored by the shell
new line type echo “This is my first script ”
this what the script should look like
echo is use for read only command you type echo ” hello world ” in terminal it will read whats in the brackets
so now we save the script so press ctrl and s to save the script name it myscript.sh and save to root
now that its saved lets see does it work so open terminal and type chmod +x myscript.sh and press enter
now type ./myscript.sh
the output should be this my first script
congrats you just wrote a simple script look lets start adding some more lines
so now we are going to man a calculator in bash to be ran in terminal
here the commands/statement we are Using
echo is one of the mostly used command.
It is used to print a line of text in standard output.
$ echo [-neE] [arg …]
The command read in the Linux is used to read the input from the keyboard.
When there are a lot of if statement in Shell and it becomes confusing. Then it is good to use case statement.
4. bc Command
bc command is used for command line calculator. It is similar to basic calculator by using which we can do basic mathematical calculations. Arithmetic operations are the most basic in any kind of programming.
# the Input
echo “Enter Two numbers : ”
# Input type of operation
echo “Enter Choice :”
echo “1. Addition”
echo “2. Subtraction”
echo “3. Multiplication”
echo “4. Division”
# calulator operations
case $ch in
1)res=`echo $a + $b | bc`
2)res=`echo $a – $b | bc`
3)res=`echo $a \* $b | bc`
4)res=`echo “scale=2; $a / $b” | bc`
echo “Result : $res”
save it to Desktop or were want
now lets run it
chmod 755 myscript
YUP SNOTS IT WORKS !!!!!!
Now u know a little bit of bash now u can start making simple scripts to automate your life in hacking