kill process in bash

• Echo statements always require double quotes in bash script.
• use ${variable} to reference the variable.

Sample script 1:

#!/bin/bash

echo "hi there"
echo "my current directory is "
pwd

echo "contents of the directory is"
ls

#!/bin/bash

a=3
b=4 
c= $a + $b 
echo "$c"

output:
3+4

#!/bin/bash

word="fun"

echo "linux is $word"
echo "bash is $word"
echo "Test cricket is $word"

Output:

linux is fun
bash is fun
Test cricket is fun

#!/bin/bash
echo "file contents are $(ls)"
echo "present directory is $(pwd)}"

now=$(date) 
echo "system date and time is $now"

name=$(whoami) # or use $(USER)
echo "my name is $name and using this machine on $now"

• multiplication is calculated by expr 100 /* 4, addition is calculated by expr 2 + 3, division is calculated by expr 2 / 3.

#!/bin/bash

var=33
total= expr $var + 4
echo "total is $total"

Here are some ways to add two numbers and store the result in a variable in Bash:
Using the let command.
Code

num1=10
num2=20
let sum=$num1+$num2
echo "The sum is $sum"

This will print the following output:
Code
The sum is 30

num1=10
num2=20
sum=$(expr $num1 + $num2)
echo "The sum is $sum"

This will also print the following output:

Code
The sum is 30

num1=10
num2=20
sum=$(echo $num1 + $num2 | bc)
echo "The sum is $sum"

This will also print the following output:
The sum is 30