If it's zeros to a file, then the obvious one is:
dd if=/dev/zero of=file.bin bs=1 count=128
Note that this is pretty inefficient as it goes, as it does single byte writes. You could just as easily use:
dd if=/dev/zero of=file.bin bs=128 count=1
bs' is the 'block size' andcount` is how many blocks. Better to write one block than lots of little ones!
Note that the above commands do not append to
file.bin, they overwrite it. One way round that is:
dd if=/dev/zero bs=128 count=1 >> file.bin
Explanation: in the absence of
dd writes to standard output, which is then appended to the output file.