Hacker Dictionary
Browse the Dictionary...
All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Navigation Random Term
  • link farm
    [UNIX] n. A directory tree that contains many links to files in a master directory tree of files. Link farms save space when... VIEW ENTIRE DEFINITION

  •  View Definition: dd 


    /dee-dee/ [UNIX from IBM JCL] vt. Equivalent to cat or BLT. This was originally the name of a UNIX copy command with special options suitable for block-oriented devices. Often used in heavy-handed system maintenance, as in "Let's `dd' the root partition onto a tape, then use the boot PROM to load it back on to a new disk". The UNIX `dd(1)' was designed with a weird, distinctly non-UNIXy keyword option syntax reminiscent of IBM System/360 JCL (which had an elaborate DD `Data Definition' specification for I/O devices); though the command filled a need, the interface design was clearly a prank. The jargon usage is now very rare outside UNIX sites and now nearly obsolete even there, as `dd(1)' has been deprecated for a long time (though it has no exact replacement). Replaced by BLT or simple English `copy'.