Milind's Bash Scripting Tutorial

Contents

To see which shell

• which $SHELL

Use this command to Shebang

• #!/bin/bash

Printing Hello World

• echo "hello world"
• echo -n “Prints and goes to a new line for input“

Add Delay

• sleep

IMPORTANT TO SEE THE PERMISSIONS OF FILES -- read(r) / write(w) / exe (x)

• ls -l

TO MODIFY THESE PERMISSIONS use CHMOD

• eg. add an executable permission modification : chmod +w

  TO run this shell script as milind.sh

  • ./milind.sh

CONDITIONS

• if condition :

  if [ $((x % 2)) == 0 ]; then \n echo “Number is Even” \n fi

• fi : means finish if

• if [ condition1 ]; then \n # Code to be executed if condition1 is true \n elif [ condition2 ]; then \n # Code to be executed if condition2 is true \n elif [ condition3 ]; then \n # Code to be executed if condition3 is true \n else \n # Code to be executed if none of the conditions are true \n fi

FOR LOOPS

for n in a b c;
do
   echo $n
done

• for n in {1..5}; do echo $n done

STRINGS

string1="GeekForGeeks"
string2='Geeks for Geeks'
string3=2345656778

#Printing the strings

echo $string1
echo $string2
echo $string3

string="geeksforgeeks"
echo "The length of the string is : ${#string}"