HJSplit is a popular freeware program to split and recombine files. The program is available on Windows, Linux and a variety of other platforms.
Why should one want to split and recombine files? For instance, think of a file of 50 Mb, and try to send it to a friend, post it in a newsgroup or upload it to a Website or FTP server. It is usually easier to send/receive, upload/download smaller parts than handle the entire file in one go.
HJSplit can also be useful for backups. A file of e.g. 10 gigabytes in size can be split into smaller parts which then can be burned to CD's, DVDs, copied to USB sticks or uploaded to an online backup service.
HJSplit for Windows and Linux support file sizes of over 100 Gigabytes, MD5 checksums, file-compare, "run without install" and both editions are fully portable.
The software does not need to be installed, so you can simply run the executable file. Since this makes it portable, you can directly run HJSplit from any external device.
There are four main functions here: split, join, compare, and check sum.
In order to split a file, you must select the source file, output destination, and split file size (in KB or MB).
When joining two or more files, make sure they are all placed in the same directory, as HJSplit automatically finds them.
For instance, let's say you have splitted a file into three parts, but only two of them are in the same directory. The joinner requests you guide it to the first part. Since the third part is not located in the same root, the joiner will append ".joined" to the output file name (which contains only the first and second part). But the file itself is unusable without the last part.
The Compare function is very basic. It says whether any two selected files have the same length or not.
Furthermore, the Checksum function calculates and lets you copy the MD5 checksum of any file you input.
The program uses a small amount of system memory.