A simple program which searches for a pattern in a binary file and patches it with a new one!
rutcher -s 12345678 -r 90909090 ~/patchme.exe /tmp/patched.exe
This will search for the bytes 0x12 0x34 0x56 0x78
and patch every occurrence with 0x90 0x90 0x90 0x90
.
Note: since this tool is aimed in patching binary files, the patterns should probably have the same length.