In Linux you can use split and join commands to split large files into smaller files or join many smaller files into a large file. This kind of operations are often necessary when you are dealing with large quantities of data.
split
Following is the default functionality of split. It splits a large file every thousand lines and creates new files.
$ split largefile.txt
$ ls
largefile.txt xaa xab xac xad
$ wc -l *
3285 largefile.txt
1000 xaa
1000 xab
1000 xac
You can also define the number of lines you want in each file
$ split -l 2000 largefile.txt
$ ls
largefile.txt xaa xab
$ wc -l *
3285 largefile.txt
2000 xaa
2000 xab
2000 xac