Take a look at the Windows ports of
Gnu Coreutils. The Split command may do what you want:
C:\$DATA\$installers\copy-into-winnt>split --help
Usage: split [OPTION] [INPUT [PREFIX]]
Output fixed-size pieces of INPUT to PREFIXaa, PREFIXab, ...; default
PREFIX is `x'. With no INPUT, or when INPUT is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-a, --suffix-length=N use suffixes of length N (default 2)
-b, --bytes=SIZE put SIZE bytes per output file
-C, --line-bytes=SIZE put at most SIZE bytes of lines per output file
-l, --lines=NUMBER put NUMBER lines per output file
--verbose print a diagnostic to standard error just
before each output file is opened
--help display this help and exit
--version output version information and exit
SIZE may have a multiplier suffix: b for 512, k for 1K, m for 1 Meg.
Report bugs to <
[email protected]>.