The command-syntax is:
csplit [OPTION]... FILE PATTERN...
The patterns may be line numbers or regular expressions. The program outputs pieces of the file separated by the patterns into files xx00, xx01, etc., and outputs the size of each piece, in bytes, to standard output.
The optional parameters modify the behaviour of the program in various ways. For example, the default prefix string (xx) and number of digits (2) in the output filenames can be changed.
As with most Unix utilities, a return code of 0 indicates success, while nonzero values indicate failure.
Comparison to split
The split command also splits a file into pieces, except that all the pieces are of a fixed size (measured in lines or bytes).