Ĭertain features of dd will depend on the computer system capabilities, such as dd's ability to implement an option for direct memory access. By default, dd reads from stdin and writes to stdout, but these can be changed by using the if (input file) and of (output file) options. It uses the syntax option= value for its command-line options rather than the more standard - option value or - option= value formats. The command line syntax of dd differs from many other Unix programs.
#Continuously read and copy log file windows#
The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities. The version of dd bundled in GNU coreutils was written by Paul Rubin, David MacKenzie, and Stuart Kemp. This is inherited by IEEE Std 1003.1-2008 ( POSIX), which is part of the Single UNIX Specification. The dd command is specified since the X/Open Portability Guide issue 2 of 1987.
Originally intended to convert between ASCII and EBCDIC, dd first appeared in Version 5 Unix. dd is sometimes humorously called "Disk Destroyer", due to its drive-erasing capabilities. The interface is redesigned in Plan 9's dd command to use a command-line option style. Raymond says "the interface design was clearly a prank". The command's syntax resembles a JCL statement more than other Unix commands do, so much that Eric S. The name dd is an allusion to the DD statement found in IBM's Job Control Language (JCL), in which it is an abbreviation for "Data Definition". 4.2.1 Master boot record backup and restore.The dd program can also perform conversions on the data as it is copied, including byte order swapping and conversion to and from the ASCII and EBCDIC text encodings. As a result, dd can be used for tasks such as backing up the boot sector of a hard drive, and obtaining a fixed amount of random data.
#Continuously read and copy log file drivers#
On Unix, device drivers for hardware (such as hard disk drives) and special device files (such as /dev/zero and /dev/random) appear in the file system just like normal files dd can also read and/or write from/to these files, provided that function is implemented in their respective driver. Unix, Unix-like, Plan 9, Inferno, Windowsĭd is a command-line utility for Unix, Plan 9, Inferno, and Unix-like operating systems and beyond, the primary purpose of which is to convert and copy files.
Various open-source and commercial developersĬoreutils: git. (from your subject and post) and post in the regular forums at any time.Command-line utility for Unix and Unix-like operating systems dd Original author(s) Of course, you can always post a descriptive subject text, remove words like "Urgent" etc. If you have posted a question in the regular forum with a subject "Urgent" "Emergency" or similar idea, we will, more-than-likely, close your thread and post this reply, redirecting you to the proper forum. However, we will treat your post with a higher priority and give our best efforts to help you. We monitor this forum to help people with emergencies, but we do not not guarantee response time or best answers. Posting a new question in the Emergency UNIX and Linux Support Forum requires forum Bits. This forum is given a higher priority than our regular forums. For this reason, posting questions with subjects like "Urgent!" or "Emergency" and demanding a fast reply are not permitted in the regular forums.įor members who want a higher visibility to their questions, we suggest you post in the Emergency UNIX and Linux Support Forum. Everyone at the UNIX and Linux Forums gives their best effort to reply to all questions in a timely manner.
0 kommentar(er)
