Doing this offline is probably easier and faster. dd if=/dev/urandom of=./test.img bs=1M count=400 2>/dev/null;md5sum ./test.img;split -n4 ./test.img _spli

Doing this offline is probably easier and faster. dd if=/dev/urandom of=./test.img bs=1M count=400 2>/dev/null;md5sum ./test.img;split -n4 ./test.img _split. ;ls -alh test* _split*;rm -f ./test.img;cat _split.* > ./test_joined.img;md5sum ./test_joined.img 30e3089819b9af5985b90014cf68360b ./test.img 100M Mar 4 15:49 _split.aa 100M Mar 4 15:49 _split.ab 100M Mar 4 15:49 _split.ac 100M Mar 4 15:49 _split.ad 400M Mar 4 15:49 test.img 30e3089819b9af5985b90014cf68360b ./test_joined.img Explanation: dd : create a file md5sum : get checksum of the file split -n4 : split file into 4 chunks ls : view what we created rm : remove the original input file cat : join the files back together md5sum : verify the joined file matches the original The above commands are already on Mac and Linux. You can get these for windows by installing Cygwin or the Linux Subsystem.