We cannot assign tags to files in a direct manner in a bare-POSIX environment. The technical difficulty lies in the POSIX definition which lacks storage of meta-info associated with a file. Though the non-POSIX Extended file attributes laid down the mechanism to fill in this gap, GNU userland applications or desktop environments do not utilize them in general. ¹⁾This forces us to invent new means of storing tags. Databases are neat, but they do not integrate well with the GNU environment, they require special interfaces and tools for access and management ²⁾. Revisiting an old friend seems to offer a good solution, though: symbolic links.

You can create a seperate directory for each tag, then create symlinks under respective directories. That is to say, if file1 should be tagged with tag1 and tag7, you should create a symlink, pointing to file1, under tag1 and tag7 directories. Advantage in doing so is, you can easiliy access to all files tagged with, say, tag3, just by going into tag3 dir. You can manage your “database” without requiring special interfaces. Access to files with a desired tag takes O(1) time. But symbolic links, by their nature, can be broken: if you move file1 to some other place, all links pointing to it are dead (as also pointed out in this more recent review).

symutils addresses this issue with symfix(1) tool. It can, somewhat automated, somewhat manually, fix the broken links. There're other handy tools for handling symlink tags in symutils ³⁾. lssym(1) looks for common symlinks under given directories, such that you can list what tags are associated with given a file and find files tagged with given tag list, so you can ask it to “find the files tagged with tag1 and tag3”, for instance. replsym(1) helps you with move a target for symbolic links.

Alternatives

Future