5

When linking a directory to root, I get this error:

$ ln -s ~/inbox/ /
$ ln: //: Is a directory

Bash autocompletes the directory path by adding a /. I've tried escaping without success.

$ ln -s ~/inbox /

works though. Why is this?

Gilles 'SO- stop being evil'
  • 807,993
  • 194
  • 1,674
  • 2,175
Igorio
  • 7,279
  • 7
  • 20
  • 11
  • 2
    What you wrote cannot work, I think you have to add more detail to your question. Also, are you working as root? Also, what exact OS are you on? – jippie May 09 '12 at 18:25
  • What OS is this? Is it GNU Coreutils, or the BSD utils? – jsbillings May 09 '12 at 19:46
  • I don't think it's coreutils. My version puts the file name in quotes, e.g. `ln: 'foo': hard link not allowed for directory`. – Mikel May 09 '12 at 20:43

2 Answers2

4

In pathname resolution, having a trailing / is equivalent to a trailing /. — in other words, ~/inbox/ is equivalent to ~/inbox/. in this context. So the ln command is trying to create a link called . in the root directory (and, unsurprisingly, failing).

Zsh removes the trailing / when you press Space after completing a directory (unless configured not to do so). I don't know if bash can be made to do this.

Gilles 'SO- stop being evil'
  • 807,993
  • 194
  • 1,674
  • 2,175
  • Very interesting. `Pathname resolution` also says that symlinks should be resolved. But when you do `ln symlink blah`, `blah` should point to `symlink`, not what `symlink` points at. – Mikel May 10 '12 at 04:16
0

Is that exactly what you ran?

Is a directory looks like your OS printing the EISDIR error, which could happen two ways:

Trying to overwrite an existing symlink that points to a directory.

$ cd $(mktemp -d)
$ mkdir dir
$ ln -s dir dir    # this creates dir/dir
$ ln -s dir dir    # this fails, because dir/dir already exists
ln: failed to create symbolic link `dir/dir': File exists

Trying to create a hard link to a directory.

$ cd $(mktemp -d)
$ mkdir dir
$ ln dir dirlink
ln: `dir': hard link not allowed for directory

If it is what you were running, what does type ln or alias ln print?

Mikel
  • 56,387
  • 13
  • 130
  • 149
  • I think it is good to explain what `cd $(mktemp -d)` does. Not everybody is familiar with this construction. – jippie May 09 '12 at 21:07
  • 1
    It creates a new directory somewhere under `/tmp`. It makes sure that the files I'm using in my examples don't already exist so that everyone can get try running the commands and get the same results. – Mikel May 09 '12 at 21:18