Linux – Difference Between Soft (Symbolic) Link and Hard Link

filesystemshardlinklinuxsymlinkunix

I hear that you can now create soft links in Vista too. So, what is the difference between a soft (symbolic) link and a hard link on UNIX/Linux/Vista?

Are there advantages of using one over the other? Or do they just serve two distinct purposes?

Best Answer

A hard link traditionally shares the same file system structures (inode in unixspeak), while a soft-link is a pathname redirect.

  • Hardlinks must be on the same filesystem, softlinks can cross filesystems.
  • Hardlinked files stay linked even if you move either of them (unless you move one to another file system triggering the copy-and-delete mechanism). Softlinked files break if you move the target (original), and sometimes when you move the link (Did you use an absolute or relative path? Is it still valid?).
  • Hardlinked files are co-equal, while the original is special in softlinks, and deleting the original deletes the data. The data does not go away until all hardlinks are deleted.
  • Softlinks can point at any target, but most OS/filesystems disallow hardlinking directories to prevent cycles in the filesystem graph (with the exception of the . and .. entries in unix directories which are hard links).
  • Softlinks can require special support from filesystem walking tools. Read up on readlink (2).

(Some details brought back to mind by mat1t. Thanks.)

Related Topic