การสร้างและใช้งานลิงก์สัญลักษณ์

A link is a filesystem entry that points to another file. Links let one file appear in multiple places without duplicating its data, saving space and easing organization.

Linux has two kinds: symbolic links and hard links.

A symbolic link (symlink) is a small file holding a path to its target. Create one with ln -s: the target first, then the link name.

ls -l shows symlinks with an arrow pointing to their target, and the type character l at the start of the permissions.

Reading or writing through a symlink transparently affects the target. Editing current.log edits /var/log/app.log.

A hard link is a second name for the exact same data on disk. Both names are equal; deleting one leaves the data until the last link is gone.

Key differences:

• Symlinks can cross filesystems and link directories; hard links cannot.
• A symlink breaks if its target moves; a hard link keeps the data alive.
• Symlinks store a path; hard links share an inode.

If a symlink's target is deleted or moved, the link becomes dangling. Accessing it fails. ls often shows broken links in red.

Use readlink to print where a symlink points, and readlink -f to resolve the full real path through chained links.

To repoint a symlink, use ln -sf to force-replace it. To remove a link, rm deletes the link itself, never the target file.

Symlinks shine for:

• A stable current path pointing at the latest versioned release.
• Putting config files in a dotfiles repo, linked into $HOME.
• Sharing a dataset across projects without copies.

To audit existing links, combine ls with a filter. The find command can list every symlink under a path, helping you spot broken or stray ones.

You learned to work with links: create symlinks with ln -s, inspect them with ls -l and readlink, understand hard vs symbolic differences, recognize broken links, repoint with ln -sf, and apply them to releases, dotfiles, and shared data.