File

Core Idea

A file is a named filesystem object that usually stores bytes plus metadata such as owner, permissions, size, and timestamps.

Commands To Try

ls -l ~/src/pages/index.md
stat ~/src/pages/index.md
file ~/src/pages/index.md
cat ~/src/pages/index.md

ls -l shows compact metadata. stat shows detailed metadata. file guesses content type. cat prints file bytes as text.

Content Versus Metadata

File content is the bytes inside the file. Metadata is information about the file: name, owner, group, mode, size, timestamps, and type. Editing a file changes content. chmod changes permission metadata.

Source Versus Generated File

In this course:

• Source file: ~/src/pages/index.md.
• Generated file: ~/public_html/index.html.

Edit source. Rebuild generated files.

Common Confusions

• File extension is a convention, not proof. Use file when content matters.
• A filename and the bytes it points to are related but not identical concepts.
• Deleting a file path removes a directory entry; recovery depends on backups or source regeneration.
• cat is for text. Use file, strings, or xxd for unknown data.

Proof Check

Run stat on one source file and identify size, owner, permissions, and modification time.

Docs Pointers

• Run man stat, man file, and man chmod.
• Read Filesystem, File Encoding, and Permissions.