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## Session-10. Control Statements-if,elif,else

Control statements :
If statement
Case statement
While loop
For loop
Until loop
Break
Exit

### If statements

simple if
If-ele
nested if

If [ condition ]
Then
Action
fi

Case:

…..

Esca

x=10===> Assignment operator
X = 10 ===> before and after space ==comparison operator

``````#!/bin/bash

if [  \$name = "Shashi"  ]
then
echo "hello shahsi good morning"
fi
echo " how are you : \$name "``````

#### Method 2:

If [ condition ];then
Action
fi

``````#!/bin/bash

if [  \$name = "Shashi"  ] ;then
echo "hello shahsi good morning"
fi
echo " how are you : \$name "``````

2)if-else

If [ condition ]
then
First action
else
Action 2
fi

3) Nested if

If [ condition1 ];then
First action
If[ condition2 ]; then
……..
If[ cond3 ]; then

``------``

else

fi

## else

fi
fi

`` Action 2``

fi

If [ condition1 ]
then
First action
elif [ cond2 ]
then
Action 2
elif [ cond3 ]
then
Action 3
else
Default action
Fi

### Greater number

``````#!/bin/bash
read -p "enter first number  : " a
read -p "enter 2nd number  : " b

if [  \$a -gt \$b ] ;then
echo "Bigger number is \$a"
else
echo "Bigger number is \$b"
fi

#!/bin/bash
read -p "enter first number  : " a
read -p "enter 2nd number  : " b
if [  \$a -eq \$b ] ;then
echo "both numbers are equal"
elif [  \$a -gt \$b ] ;then
echo "first number is  greater than second number"
else
echo "second  number is  greater than first number"
Fi

#Find the greatest of three numbers

#!/bin/bash
read -p "enter first number  : " a
read -p "enter 2nd number  : " b
read -p "enter 3rd number  : " c
if [  \$a -gt \$b  -a \$a -gt \$c] ;then
echo "\$a is the bigger name"
elif [  \$b -gt \$c ] ;then
echo "\$b   is  biggest"
else
echo "\$c is biggest"
fi

#Subject failed

#!/bin/bash
read -p "enter first subject marks: " a
read -p "enter 2nd subject marks  : " b
read -p "enter 3rd subject marks  : " c
if [  \$a -lt 35 ] ;then
echo "1st subject failed"
elif [  \$b -lt 35 ] ;then
echo "2nd subject failed"
elif [  \$c -lt 35 ] ;then
echo "3rd subject failed"
else
echo "Congrats you passed all  3subjects "
fi``````

Favorite brand and corresponding info :

#### Script +ve o r -ve number

``````#!/bin/bash

read -p "enter any interger number " n

if [ \$n -lt 0 ] ; then

echo "\$n is negative number"

else

echo "\$n is postive number"

fi``````

#### Even number or not

``````#!/bin/bash
read -p "enter any interger number " n
if [ \$[n%2] -eq 0 ] ; then
echo "\$n is even number"
else
echo "\$n is odd number"
fi``````