symlinks

A symbolic link, or symlink, is a special kind of file that serves as a reference to another file or directory. It contains a pathname to the target rather than the data of the target itself. When a program accesses a symlink, the operating system transparently follows the path to the target. If the target is moved or deleted, the symlink may become dangling and no longer resolves to a valid object.

Symlinks are distinct from hard links. A hard link is another directory entry that points to the same underlying inode as the target; a symlink is a separate file that points to a pathname. Symlinks can cross filesystem boundaries and can reference directories, whereas hard links typically cannot cross file system boundaries and are usually not used for directories.

Resolution and behavior depend on the system. Many Unix-like systems offer readlink or similar utilities to obtain the target path. System calls like stat and lstat differ in how they treat symlinks: stat follows the link to the target, while lstat reports the link itself. Symlinks can point to absolute or relative paths; relative targets are resolved relative to the link’s location.

Creation and removal are straightforward. In Unix-like environments, the command ln -s target link creates a symlink named link that points to target; removing the link (rm link) deletes only the link, not the target. On Windows, symbolic links can be created with mklink, with differences for files and directories, and there are also junctions that behave differently.

Common uses include aliasing long paths, redirecting libraries or data directories, and enabling flexible package layouts. Potential issues include broken or circular links, security concerns when following links in web servers or sandboxed environments, and portability considerations when moving data between systems.