To split big files, split command can be used. Below is command used to split 400MB file named bigfile into 100MB chunk files named smallfile0*
$ split -b 100M -d --verbose bigfile smallfile
creating file 'smallfile00'
creating file 'smallfile01'
creating file 'smallfile02'
creating file 'smallfile03'
where -b is for byte size, -d is for numeric suffixes and smallfile is the prefix to be used
The output is:
bigfile smallfile00 smallfile01 smallfile02 smallfile03
To recover back the splitted files into a file named newbigfile:
$ cat smallfile0* > newbigfile