UNIX for Dummies Questions & Answers

Someone asked me a question today about the difference between a hard link and a soft link. That got me thinking and maybe someone can answer.

Why would I ever use a hard link if I can use a soft link instead?

You can do a "ls -l somefile" and get a count of the hard links. Counting soft links is rough.

Hard links are co-equals. Unlink either of them and the data remains. A daggling softlink is worse than useless.

A related issue... "ln falsetarget somecopy" will fail if falsetarget does not exist. "ln -s" would not detect a problem.

It takes some time to travel down a symlink to the target. Hards links are a very little bit faster.

All that said, I prefer hardlinks to files in the same directory. ls -l /usr/bin to see what I mean. Otherwise I tend to go with soft links.

My preference is similar to Perderabo.

I prefer hard links in the same filesystem. On HPUX, in one case, we hard link /etc/group and /etc/logingroup. Since you can't hard link between 2 different filesystems (mount points), you MUST use a softlink in those cases.

To tell if 2 files are hardlinked you can run:

# ls -li /path/to/filename1 /path/to/filename2