Splitting up large files

This is one of those things that I need to do occasionally, but not often enough that I've been able to commit it to memory.

 split -b 4000m large_file large_file.

This will split a the large_file file into 4Gb files with filenames large_file.aa, large_file.ab, etc. Before doing this, it really helps to make sure you've got enough space for the new files - ie, at least as much free space as the file you are splitting!

To get the parts back together:

 cat large_file.* > large_file