Basic scripts -2
Shell Script:
echo $SHELL --> to check default shell
#!/bin/bash --> shebang --> invokes bash shell
exp1.sh
#!/bin/bash echo "Hi \nThis is devops class" echo "Started on Nov"
execution shell script:
./exp1.sh bash exp1.sh sh exp1.sh
================================================
exp2.sh
#!/bin/bash echo "This is $1 class" echo "Started on $2"
execution: ./exp2.sh Devops Nov
================================================
Input arguments
if the argument from 1 to 9
we used as $1, $2, $3 ... $9if the argument from 10th onwards we used as ${10}, ${11}....
$1 --> first input argument $2 --> Second input argument $0 --> Shell script name
================================================
exp3.sh
#!/bin/bash name="Test" month="Nov" num="2022" echo "This is $name platform and month is $month" echo "The number will be $num"
================================================
If statement:
if [ condition ]
then
execution
else
execution
fi
======================================
exp4.sh
#!/bin/bash
if [ $1 -eq 5 ]
then
echo "$1 is Five"
else
echo "$1 is not Five"
fi
=========================================
parameters:
-eq --> equals
-lt --> less than
-le --> less than or equal
-ge --> greater than or equal
-gt --> greater than
-ne --> not equal
=========================================
exp5.sh
write a shell script to find biggest of two numbers.
2 3
#!/bin/bash
if [ $1 -gt $2 ]
then
echo "$1 is Big"
else
echo "$2 is Big"
fi
===========================================
exp6.sh
#!/bin/bash
if [ $# -ne 2 ]
then
echo "Enter only two arguments"
exit
fi
if [ $1 -gt $2 ]
then
echo "$1 is Big"
else
echo "$2 is Big"
fi
===========================================
special characters of global variables:
$? --> status of last executed command
0 --> means success
non-zero --> failure
$$ --> process ID of current running process
$! --> process ID of last command went into background
$* --> All the arguments pass to a shell script
$@ --> All the arguments pass to a shell script stored in array format [ 1 23 55 66 ]
$# --> Total number of arguments pass to a shell script
======================================================================================
syntax for "for" loop
for i in List
do
commands/execution
done
======================================================================================
Syntax for "While" lopp
while [ condition]
do
commands/execution
done
======================================================================================
Write a shell script to check whether given name is a file or directory or link or doesnot exist?
#!/bin/bash
echo "Enter the name to check:"
read name
if [ -f $name ]
then
echo "$name is file"
elif [ -d $name ]
then
echo "$name is a directory"
elif [ -l $name ]
then
echo "$name is a link"
else
echo "$name doesnot exit"
fi
======================================================================================
Assignments:
1. Biggest 3 no's
2. Write a shell script to check whether given name is a file or directory or link or doesnot exist,
* If its a file display the content, count how many lines content is present in that file.
* if its a directory display the file
3. Write a shell script to add, subtract, multiply and divide the two numbers
4. Write a script to find factorial of a given number
5. Write a script to add given set of numbers
======================================================================================
Last updated