dd

dd is a common UNIX program whose primary purpose is the low-level copying and conversion of raw data. dd is an abbreviation for "data definition"
It can also be used in computer forensics when the contents of a disk need to be preserved as a byte-exact copy- using cp would not be enough, since data from deleted files that may still be present on a disk are not visible through the file system interface.

The command line syntax of dd is significantly different from most other UNIX programs, and because of its ubiquity is resistant to recent attempts to enforce a common syntax for all command line tools. Generally, dd uses an option=value format, whereas most Unix programs use a -option value format. Also, dd's input is specified using the "if" (input file) option, while most programs simply take the name by itself. It is rumored to have been based on IBM's JCL, and though the syntax may have been a joke, there seems never to have been any effort to write a more Unix-like replacement.