Phil

Did you actually read the docs?

On *ix, a link is a pointer to another file. Sort of like shortcuts in Windows (although better); copy (amended link) duplicates the contents of a file in a new file. Creating a link tells the directory that 'any time I refer to a file named fred, I really mean the file named Dr J Fred Mbogo.'

As an analogy, which may be best understood by US residents. The White House and 1600 Pennsylvania Avenue, Washington, DC refer to the place, by different names.

The main practical difference, afaik, is that if you edit a link, then you are editing the original as well (well, they are the same thing).

However, if you edit a copied file, then the original is unchanged.

Gotta go - my granny wants to learn to suck eggs...

map{$a=1-$_/10;map{$d=$a;$e=$b=$_/20-2;map{($d,$e)=(2*$d*$e+$a,$e**2
-$d**2+$b);$c=$d**2+$e**2>4?$d=8:_}1..50;print$c}0..59;print$/}0..20
[download]

Same goes for Windows, but that was no surprise to me.

*NIX has two kinds of links: hard and soft. link creates a hard link, in which two separate directory entries point to the same inode on the disk (which also increments the link count on that inode). symlink creates a soft (or symbolic) link in which the directory entry contains the name of the target file.

Hard links are separate, redundant entries in the filesystem. When you unlink one of them, the other still points to the file (although the inode's link count is decremented) so the contents on disk are not removed; once you unlink all directory entries pointing to the inode in question it will be put back on the free list and made available for reuse. You can detect a hard link by using the -i option to ls to show the inode number in listings; two directory entries hardlinked to the same file show the same inode number.

Symbolic links are more like pointers by name to real files. Removing a symlink just removes the pointer entry in the directory. Removing the target leaves the pointer dangling and trying to access through it will fail.

Update: Here's an example which may clarify hard links.

$ touch file1
$ ls -li file1
4210927 -rw-r--r--   1 fletch  wheel  0 Dec  8 11:15 file1
$ perl -e 'link( "file1" => "file2" ) or die "$!"'
$ ls -li
total 0
4210927 -rw-r--r--   2 fletch  wheel  0 Dec  8 11:15 file1
4210927 -rw-r--r--   2 fletch  wheel  0 Dec  8 11:15 file2
$ echo "Through file2" >> file2
$ ls -li
total 16
4210927 -rw-r--r--   2 fletch  wheel  14 Dec  8 11:15 file1
4210927 -rw-r--r--   2 fletch  wheel  14 Dec  8 11:15 file2
$ cat file1
Through file2
$ rm file1
$ cat file2
Through file2
$ ls -li
total 8
4210927 -rw-r--r--   1 fletch  wheel  14 Dec  8 11:15 file2
[download]

Update: Minor wording change to try and make it clear that its the link count that's a property of the inode itself that gets decremented.

Thanks for all that, Fletch. I learn something new every day.