LINUX File System Overview and Commands

LINUX File System Overview

• LINUX uses a hierarchical tree structure for its filesystem, starting from the root directory (/).
• Each directory can have multiple child directories but only one parent directory.
• Paths can be absolute (from root) or relative (from the current directory).

Listing LFS Directories

• The ls command displays current directory contents; it lists visible files and directories by default.
• Hidden files (starting with a period) can be shown using ls -a, which lists all entries, including . (current) and .. (parent) directories.

I-node Structure

• An i-node is a data structure that stores file metadata, including ownership, location, and pointers to file blocks.
• Each partition has its own set of i-nodes, allowing files with the same i-node number in different partitions.
• Use ls -i to display i-node numbers for files in the current directory.

Hard and Symbolic Links

• Links are a file name combined with an i-node number, allowing access to files from different locations.
• Hard links are direct duplicates of the original file; symbolic links point to the original file's location.
• Create symbolic links with ln -s existing_file new_file.

Finding Files

• Use the find command to search for files by name within a directory tree.
• Example to find .txt files: find /home -name "*.txt" -print.
• Find can filter files by type, permissions, size, etc., and can execute commands on found files with the -exec option.

Finding Text in Files

• The grep command searches for text patterns in files.
• Basic syntax: grep options pattern files, where options can modify behavior (e.g., -c counts matches, -i ignores case).
• Combine grep with find to search through files in directory trees (e.g., grep hello \find . -name "*.txt" -print``).

Sorting Files

• The sort command organizes file contents alphabetically or numerically.
• To output sorted results to another file, use redirection (e.g., sort input1.txt input2.txt > output.txt).
• The uniq command removes adjacent duplicate lines from a file, often used after sort for streamlined output (e.g., sort input.txt | uniq > output.txt).

Explore the structure and commands of the LINUX file system in this quiz. Learn about the hierarchical tree structure, directory relationships, and how to list contents using commands like ls. Test your knowledge on both absolute and relative paths as well.