This shell script creates a hard link of every file in a directory into another directory. It runs with two parameters: the first one specifies the original directory, the second one the target directory.
If the target directory doesn't already exist, it is created by the script. if there are any files in the target directory with the same name as files in the original directory, those files are skipped. The algorithm is recursive and recreates the inner structure of the original directory. Be careful with soft links, however; they created some bugs in testing. (If you know why, please let me know. You can always write a mail to code@henrikgoedeke.de)
The code is available under Creative Commons Attributions-ShareAlike 4.0 Licence