Glossary
Symbolic link (symlink)
A small file containing a path, resolved on every access.
A symbolic link is a tiny file whose content is a path to something else. Every time you open it, the system reads that path and follows it. Because it stores a path rather than a reference to an inode, a symlink can cross filesystems, point at directories, and even point at something that does not exist yet — a "broken" link.
Symlinks power two ubiquitous patterns: dotfiles kept in a git repo and linked into place, and deployment schemes where /opt/app/current points at the active release, so switching versions is one atomic link change.
See it in practice
$ ln -s /opt/app-2.4.1 /opt/app/current && readlink -f /opt/app/currentCreates a pointer and then resolves it. Switching releases is one atomic link change.
Where you'll meet it
Make one file reachable from several paths — and understand symlinks vs hard links.
Hard linkA second, equally real name for the same file.
InodeThe structure that IS a file — metadata plus pointers to its data.