Symbolic links. So, using mklink, I create a link to a directory or a file.
I can make a "hard link" - that's been supported on NTFS for ages - or I can
make a symbolic link. So, what does all that mean?
Hard links are easier to understand - For example, I have a single
PowerShell script that automatically fires off an RDP session to the name of
the computer I type in. If I look at the directory where the file is, I see:
PS > dir
Directory: Microsoft.PowerShell.Core\FileSystem::U:\psbin
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a--- 28/10/2007 3:42 PM 1278 charlie-xp2.ps1
-a--- 28/10/2007 3:42 PM 1278 core.ps1
-a--- 28/10/2007 3:42 PM 1278 dc.ps1
-a--- 28/10/2007 3:42 PM 1278 eng-vmhost-01.ps1
-a--- 28/10/2007 3:42 PM 1278 gw.ps1
-a--- 28/10/2007 3:42 PM 1278 habitat.ps1
-a--- 28/10/2007 3:42 PM 1278 homeserver.ps1
-a--- 28/10/2007 3:42 PM 1278 homesrv.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350-core-04.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350-dc-02.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350-dc-03.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350-ts-05.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350-xmpl-gw1.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350-xmpl-wsus.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350g5-1.ps1
-a--- 28/10/2007 3:42 PM 1278 hp350g5-7.ps1
-a--- 28/10/2007 3:42 PM 1278 lh-vmhost-09.ps1
-a--- 28/10/2007 3:42 PM 1278 ml350g5-7.ps1
-a--- 28/10/2007 3:42 PM 1278 sharon-xp1.ps1
-a--- 28/10/2007 3:42 PM 1278 srv1.ps1
-a--- 28/10/2007 3:42 PM 1278 ts05.ps1
-a--- 28/10/2007 3:42 PM 1278 vista.ps1
-a--- 28/10/2007 3:42 PM 1278 vmhost.ps1
-a--- 28/10/2007 3:42 PM 1278 whs.ps1
-a--- 28/10/2007 3:42 PM 1278 xp.ps1
-a--- 28/10/2007 3:42 PM 1278 xpx64.ps1
That's exactly one file and takes up one file's worth of space on the HD. I
can edit it, and the changes are automatically reflected in every other
directory entries pointing to it. I can delete any one of the 26 versions of
the file, and none of the others are affected. No one file is the "master" -
they are all exactly equal.
Symlinks, however, are a bit different. In theory, a symbolic link to a file
should behave exactly as if it were the file. That is, I should be able to
edit a file called "myfile.txt" located on C:\ when in fact the file is
only a symbolic to a file called "myfile.txt" that actually resides on
C:\Users\Charlie. That's the theory, and it almost works in Vista - as long
as you don't cross drive boundaries. I figure another round or two and
they'll get it right. The whole point to symlinks is that they're supposed
to be able to cross drive and filesystem boundaries. And for directories, by
the way, that works now - as long as you use a directory "junction" rather
than a symlink (same command, but with a /j switch). So, I get a listing
like this:
C:\>dir MyFile.txt
Volume in drive C is Vista-x64
Volume Serial Number is 0854-A72C
Directory of C:\
28/10/2007 05:31 PM <SYMLINK> Myfile.txt
[C:\Users\Charlie\Myfile.txt
1 File(s) 0 bytes
0 Dir(s) 104,245,489,664 bytes free
The idea behind symlinks is to allow a file to reside where you really want
it to, but have it appear to be somewhere else. So they're _usually_ the
same name, just different locations, though that's not a requirement. And
with a symbolic link, the "real" file is the master. The symbolic links can
be deleted without affecting the master, but delete the master and all the
rest become orphaned.
Hope that helps?
--
Charlie.
http://msmvps.com/xperts64
http://mvp.support.microsoft.com/profile/charlie.russel