File Operations in Shell Scripting

This tutorial provides a comprehensive guide to performing file operations in shell scripts. File operations are a fundamental part of shell scripting and are essential for automating tasks related to file handling.

1. Creating Files

To create a file, use the touch command:

This command creates an empty file named "filename.txt".

2. Writing to Files

You can write to a file using redirection operators. Here are a few examples:

To write a single line to a file, use the > operator:

This command writes "Hello, World!" to "filename.txt". If the file already exists, it will be overwritten.

To append a line to a file, use the >> operator:

This command appends "This is a new line." to "filename.txt".

3. Reading from Files

You can read the contents of a file using the cat command:

This command displays the contents of "filename.txt".

To read the file line by line, you can use a while loop:

4. Copying Files

To copy a file, use the cp command:

This command copies "source.txt" to "destination.txt".

5. Moving Files

To move a file, use the mv command:

This command renames "oldname.txt" to "newname.txt".

You can also use the mv command to move a file to a different directory:

This command moves "filename.txt" to the specified directory.

6. Deleting Files

To delete a file, use the rm command:

This command deletes "filename.txt".

To delete multiple files, you can specify multiple filenames:

This command deletes "file1.txt", "file2.txt", and "file3.txt".

7. Checking File Existence

You can check if a file exists using the -e option in a conditional statement:

8. File Permissions

To change file permissions, use the chmod command. Here are a few examples:

To make a file readable and writable by the owner only:

To make a file readable and writable by the owner and the group:

To make a file readable, writable, and executable by everyone:

9. Conclusion

In this tutorial, you learned various file operations in shell scripting, including creating, writing, reading, copying, moving, deleting, checking existence, and changing permissions. These operations are essential for managing files efficiently in your shell scripts.