Add readme

README.md

+# tar-split
+
+Archive a large directory in manageable chunks.
+
+## Generate
+
+```bash
+./generate large-directory/
+```
+
+A set of tar files called `file-[\d].tar` will be created in this directory.
+
+## Extract
+
+**All segments of the chunked archive must be present to untar.**
+
+If the tar files are gzipped or otherwise compressed, uncompress them back to tarballs first. They cannot, however, be individually untarred.
+
+```bash
+./extract
+```
+
+The archives will be extracted relative to this directory.
+
+## Credit & License
+
+Credit belongs to enzotib and Nemo on [StackExchange](https://unix.stackexchange.com/a/21374). 
+Licensed under CC 3.0 By-SA.