This post is originally posted on my blog site here
In this tutorial we will try to perform basic file operations like create, write, read, delete file using shell script.
Let's get started with this.
As usual lets create new file using editor of your choice, I am using vi editor.
vi fileOps.sh
This will create new file and open editor for you.
We will create all function for common operations of file and then we will call them using switch cases, so that user can perform whatever operations he want!
Script will as user to enter file name first in which he want to perform operations
#!/bin/bash # prompt user to enter file name read -p "Enter file name: " fileName Lets create functions first.
create function which will help us to create file
createFile() { touch "$fileName" echo "file created with name: $fileName" } Create function to read file
It's good habit to check if file is exists before perform operaitons, so lets check if file exists or not, then perform read operation
otherwise let user know that file does not exist
readFile(){ if [ -f "$fileName" ]; then echo "content in file as below" cat $fileName else echo "file does not exists" fi } Create function to write file
writeFile(){ echo "Enter content you want to write to file" read content echo "$content" >> "$fileName" ## append content mode echo "Content has been written to file" } here we are using append mode to write content in file, because we dont wan to loose old data.
if you dont want to use append mode then simply modify arraw operator as below
echo "$content" > "$fileName"
Create function to delete file
As mentioned above, first check if file exists or not before you delete the file
deleteFile(){ if [ -f "$fileName" ]; then rm $fileName echo "file has been deleted" else echo "File does not exists" fi } Now, all our required functions are created, lets write function calling
Here we are going to as user which operations he want to perform using switch-case conditions
echo "Choice Operation you want to perform on file" echo "1. Create File" echo "2. Read file" echo "3. Write file" echo "4. Delete file" read -p "Enter Choice" choice case $choice in 1) createFile ;; 2) readFile ;; 3) writeFile ;; 4) deleteFile;; *) echo "Invalid choice" esac That's it, we are ready to execute this script
save the file, give required permissions to file
chmod 777 fileOps.sh
Now, run this executable using below command
./fileOps.sh
Once we run below command, it will run executable, let's create new file with name sample.txt
Enter file name: sample.txt Choice Operation you want to perform on file 1. Create File 2. Read file 3. Write file 4. Delete file Enter Choice 1 file created with name: sample.txt check if file get created or not
root@Prabhu:~/shell# ls -ltr total 12 -rwxrwxrwx 1 root root 916 Jun 15 23:15 fileOps.sh -rw-r--r-- 1 root root 0 Jun 15 23:19 sample.txt root@Prabhu:~/shell# Run again to perform write operations
root@Prabhu:~/shell# ./fileOps.sh Enter file name: sample.txt Choice Operation you want to perform on file 1. Create File 2. Read file 3. Write file 4. Delete file Enter Choice3 Enter content you want to write to file this is sample content added in file Content has been written to file root@Prabhu:~/shell# Run again to perform read operations
root@Prabhu:~/shell# ./fileOps.sh Enter file name: sample.txt Choice Operation you want to perform on file 1. Create File 2. Read file 3. Write file 4. Delete file Enter Choice2 content in file as below this is sample content added in file root@Prabhu:~/shell# Run again to perform delete operations
root@Prabhu:~/shell# ./fileOps.sh Enter file name: sample.txt Choice Operation you want to perform on file 1. Create File 2. Read file 3. Write file 4. Delete file Enter Choice4 file has been deleted check if file get deleted or not
root@Prabhu:~/shell# ls -ltr total 11 -rwxrwxrwx 1 root root 916 Jun 15 23:15 fileOps.sh root@Prabhu:~/shell# 
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