Shounak Khulape

Basic Shell Scripting - 2

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Shounak Khulape
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Basic Shell Scripting - 2

Table of contents

Other If Statement

If the output is either Monday or Tuesday

  if [ "$a" = Monday ] || [ "$a" = Tuesday ]

Test if the error.txt file exist and its size is greater than zero

  if [ $? -eq 0 ]  // If input is equal to zero (0)

  if [ -e /export/home/filename ]  //If file is there

  if [ "$a" != "" ]  //If variable does not match

  if [ error_code != "0" ]  //If file not equal to zero (0)

Comparisons:

  1. -eq equal to for numbers

  2. \== equal to for letters

  3. -ne not equal to

  4. !== not equal to for letters

  5. -lt less than

  6. -le less than or equal to

  7. -gt greater than

  8. -ge greater than or equal to

File Operations:

  1. -s file exists and it not empty

  2. -f file exists and is not a directory

  3. -d directory exists

  4. -x file is executable

  5. -w file is writable

  6. -r file is readable

Shell script programs

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to create multiple files with different names.
# Date Modified: 02/26/2024
echo
for i in {1..10}
do
    touch shounak_$i
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to create multiple file upon input
# Date Modified: 02/26/2024
echo
echo "How many files do you want?"
read t
echo
echo "Files name should start with?"
read n
for i in $(seq 1 $t)
do
    touch $n.$i
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to built simple counting.
# Date Modified: 02/26/2024
echo
for i in {1..25}
do
    sleep 1
    echo $i
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to assign write permission to files
# Date Modified: 02/26/2024
echo
for i in Shounak*
do
    echo Assigning write permission to $i
    chmod a+w $i
    sleep 1
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to assign write permissions to files with total time it will take
# Date Modified: 02/26/2024
echo
total=`ls -l shounak* | wc -l`
echo "It will take $total seconds to assign permissions..."
echo
for i in shounak*
do
    echo Assigning write permission to $i
    chmod a+w $i
    sleep 1
done

do-while Scripts

  • do while The while statement continually executes a block of statements while a particular condition is true or met
#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to run for a number of seconds
# Date Modified: 02/26/2024
echo
count=0
num=10
while [ $count -lt 10 ]
do
    echo
    echo $num seconds left to stop this process $1
    echo
    sleep 1
    num=`expr $num - 1`
    count=`expr $count + 1`
done
echo
echo $1 process is stopped!!!
echo

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to run for a number of times
# Date Modified: 02/26/2024
c=1
while [ $c -le 5 ]
do
echo "Welcome $c times"
((c++))
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script will look at your current day and tell you the state of the backup.
# Date Modified: 02/26/2024
echo
NOW=$(date +"%a")
case $NOW in
    Mon)
        echo "Full backup";;
    Tue|Wed|Thu|Fri)
        echo "Partial backup";;
    Sat|Sun)
        echo "No backup";;
    *) ;;
esac

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
echo
echo Please chose one of the options below
echo
echo 'a = Display Date and Time'
echo 'b = Lsit file and directories'
echo 'c = List users logged in'
echo 'd = Check the System uptime'
echo
read choices
case $choices in
    a) date;;
    b)ls;;
    c)who;;
    d)uptime;;
    *)echo Invalid choice - Bye.
esac

Exit Status

  • 0 = OK or Successful

  • 1 = Minor problem

  • 2 = Serious trouble

  • 3-255 = Everything else

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
for i in {1..5}
do
    rm $i
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
i=1
for username in `awk -F: '{print $1}' /etc/passwd`
do
    echo "Username $((i++)) : $username"
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
ls -l /home/oracle/hello

if [ $? -eq 0 ]
then
    echo File exist
else
    echo Files does not exist
fi

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
echo hello
echo $?

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
echi hello
echo $?

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
for i in 1 2 3 4 5
do
    echo "Welcome $i times"
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
for i in khulape repo shell scripting
do
    echo See Shounak $i
done

#!/bin/bash
# Date Created: 02/26/2024
# Author: Shounak Khulape
# Description: This script is to check other if statement.
# Date Modified: 02/26/2024
i=1
for day in Mon Tue Wed Thu Fri
do
    echo "Weekday $((i++)) : $day"
done

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