To split and merge large files in linux use the split command to accomplish this:
split --bytes=1024m myfile.iso chunk_file_
That command will split myfile.iso into files that are 1024 MB in size (1GB=1024MB) and name the various parts chunk_file_aa, chunk_file_ab, etc. You can specify b for bytes, k for Kilobytes and m for Megabytes to specify sizes.
To join the files back together on Linux:
cat chunk_file_* > myjoined_file.iso
Similarly to join the split files on a Windows machine, use the copy command:
copy /b chunk_file_* myjoined_file_windows.iso
If You prefer GUI app try HJ-Split. It is a popular freeware program to split and recombine files. The program is available on Windows, Linux and a variety of other platforms.
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 following platforms are supported:
Windows
Linux
MAC
BSD
Java
PHP
Amiga
Windows 3.x
DOS
OS/2
All HJSplit editions are compatible with each other and allow you to exchange files between different operating systems. E.g. a file split on Linux can be joined on Windows 7 and vice versa.
http://www.hjsplit.org/
