Links

On Mac and Windows, it is very useful to create shortcuts. The Unix command line has a similar mechanism called a link.

If a processing tool requires a different organization or naming strategy than you used, links can save you from having to rename and reorganize! Links also take very little space compared to your files! Links are created with the command ln (link), generally used with the flag -s (symbolic). For example, the following command creates a tiny file named blah which points to (is a shortcut to) Documents.

Link Examples

The following creates a tiny file named blah which points to (is a shortcut to) Documents

If you ask for a directory listing ls -l after this, you'll see the link, like this (that is a lower case `L` for `link`):

Note the permissions start with an l and that blah points to Documents.

Don't worry!

If you rm blah, Documents is untouched!

Links with the same name but different location

If you are in a directory and want a symbolic link with the same name as the target, then simply specify the target. In the following example, I create two sibling directories (kithen and larder), then navigate into one (kitchen) and link to the other (larder). This results in a link in the kitchen that goes directly to the larder, without affecting the existence of the main larder directory.

Caution

If you store links on a backup drive, or move links, they may not survive!
For example, the Globus file transfer tool does not correctly transfer links!

You'll get some experience using links when you play the next installment of bashcrawl.

In this 3.5-minute video, Tom Hicks discusses file linking.

Unix 6: Unix commands