Chapter 8: Working with Files and Directories

Learn how to manage files and directories in Bash, including creating, deleting, copying, moving files, changing permissions, and navigating the filesystem.

In this chapter, we’ll explore essential commands for working with files and directories in Bash, allowing you to efficiently navigate and manipulate the filesystem within your scripts.

Navigating the Filesystem

To move between directories in Bash, use the cd command:

# Changing to a specific directory
cd /path/to/directory

# Moving up one level
cd ..

# Returning to the previous directory
cd -

Creating Files and Directories

Bash provides commands to create new files and directories:

touch: Creates a new, empty file.
mkdir: Creates a new directory.

# Example: Creating a file and directory
touch newfile.txt
mkdir new_directory

Copying and Moving Files

The cp and mv commands allow you to copy and move files and directories:

# Copying a file
cp file.txt /path/to/destination

# Moving (or renaming) a file
mv file.txt newname.txt

In the first example, file.txt is copied to a new location. In the second, file.txt is renamed to newname.txt.

Deleting Files and Directories

To remove files or directories, use the rm and rmdir commands:

# Removing a file
rm file.txt

# Removing an empty directory
rmdir empty_directory

# Removing a directory and its contents
rm -r directory_name

The -r flag is used with rm to delete a directory and all its contents.

Viewing and Changing File Permissions

Each file and directory has specific permissions for the owner, group, and others. Use ls -l to view permissions and chmod to change them:

# Viewing permissions
ls -l file.txt

# Changing permissions
chmod 644 file.txt  # Read/write for owner, read-only for group and others

In the example, chmod 644 file.txt sets the file permissions so that the owner can read and write, while the group and others can only read.

Finding Files and Directories

The find command is a powerful tool for searching files and directories based on name, type, and other criteria:

# Finding files by name
find /path/to/search -name "filename.txt"

# Finding directories
find /path/to/search -type d -name "directory_name"

In these examples, find searches for files or directories matching the specified name within a given path.

Reading File Contents

Use commands like cat, less, and tail to view file contents:

cat: Displays the entire file contents.
less: Allows for interactive reading, scrolling through the file.
tail: Shows the last few lines of a file (useful for monitoring logs).

# Viewing the content of a file
cat file.txt

# Viewing the last 10 lines of a file
tail file.txt

Summary and Next Steps

In this chapter, we explored how to work with files and directories in Bash, including creating, copying, moving, and deleting files and directories, as well as changing permissions and searching for files. In the next chapter, we’ll look at process management in Bash, enabling you to control and monitor running processes within your scripts.