symbolic links
Tool Tip: Junction for Windows XP
During my years at university I spent majority of my time on a command line, working on unix systems. One of the things I loved about unix was the ability to create symbolic links.
A symbolic link allows you to ghost the location of a file or folder to another location on your file system. This means that you can create a symbolic link from a folder (e.g. /myproject/tools/nant ) which points to another folder on the file system (e.g. /common/tools/nant/). The main benefit of doing this means that you can link to a common file or folder from many projects and maintain just one copy of that file or folder. Reducing duplication is what the DRY principle is all about, so you know its good.
Now that I’m mainly using Windows as my development OS, I don’t have symbolic links anymore. Vista has them under a different name but that won’t help anyone using Windows XP. That’s where Junction comes in handy.
Junction - A symbolic link tool for Windows
After downloading junction, I placed the executable file into C:WINDOWSSystem32 so that it will be available from the command line (i.e. it will exist in the “path” environment variable). The next step is to now create a junction!
Give this a try:
C:>junction.exe c:Test c:WINDOWS |
After completing, you should be able to see the following:
C:>dir Directory of C: 11/11/2008 23:32 0 AUTOEXEC.BAT 11/11/2008 23:32 0 CONFIG.SYS 15/01/2009 06:31 <DIR> Documents and Settings 11/11/2008 23:36 <DIR> Intel 10/03/2009 15:39 <DIR> Program Files 11/11/2008 23:43 173 Setup.log 11/03/2009 13:53 <JUNCTION> Test 09/03/2009 13:44 <DIR> WINDOWS 3 File(s) 173 bytes 5 Dir(s) 136,112,881,664 bytes free |
Notice that Windows recognises the new folder as a Junction, not a Directory. Now have a look inside C:Test
C:>dir Test Directory of C:Test 09/03/2009 13:44 . 09/03/2009 13:44 .. 09/03/2009 13:44 0 0.log 11/11/2008 15:18 <DIR> addins 19/06/2008 23:20 57,344 ALCMTR.EXE 19/06/2008 23:42 2,808,832 ALCWZRD.EXE 11/11/2008 15:22 <DIR> AppPatch 14/04/2008 12:00 1,272 Blue Lace 16.bmp 14/04/2008 12:00 82,944 clock.avi 11/11/2008 23:28 200 cmsetacl.log 14/04/2008 12:00 17,062 Coffee Bean.bmp 15/01/2009 06:35 1,444 COM+.log . . . |
What you should see is all the files contained inside C:WINDOWS. This means that C:Test now points to C:WINDOWS and appears to contain all the same files.
Removing a Junction is simple:
C:>junction.exe -d c:Test |
A WORD OF WARNING: If you delete a file in the Junction folder, it will delete the real file. Be careful not to delete files inside a Junction thinking that it will only affect that Junction.
And that about sums up the simple side of Junctions! I find it really useful to link to a common tools folder in each of my projects, so that I can get to the easily from the project and only store them on disk once. Hopefully you can find a good use for them in your next project.
