<\/p>\n
If you don’t want to take any chances with your data, it is recommended that you backup hard disk partition table. Last Friday I was discussing some issues with one of our customer and he pointed out me dd command.<\/p>\n
Backup MBR with dd command<\/b><\/p>\n
\ndd the old good command which now backup partition tables even writes CDs ;). Backing up partition is nothing but actually backing up MBR (master boot record). The command is as follows for backing up MBR stored on \/dev\/sdX or \/dev\/hdX :<\/p>\n
Replace X with actual device name such as \/dev\/sda.<\/p>\n Now to restore partition table<\/b> to disk, all you need to do is use dd command:<\/p>\n dd command works with Solaris, HP-UX and all other UNIX like operating systems. Read man page of dd for more info.<\/p>\n *************************************************<\/p>\n man dd <\/b><\/p>\n NAME SYNOPSIS DESCRIPTION bs=BYTES cbs=BYTES conv=CONVS count=BLOCKS ibs=BYTES if=FILE iflag=FLAGS obs=BYTES of=FILE oflag=FLAGS seek=BLOCKS skip=BLOCKS status=noxfer BLOCKS and BYTES may be followed by the following multiplicative suffixes: xM M, c 1, w 2, b 512, kB 1000, K 1024, MB 1000*1000, M Each CONV symbol may be:<\/p>\n ascii from EBCDIC to ASCII<\/p>\n ebcdic from ASCII to EBCDIC<\/p>\n ibm from ASCII to alternate EBCDIC<\/p>\n block pad newline-terminated records with spaces to cbs-size<\/p>\n unblock lcase change upper case to lower case<\/p>\n nocreat excl fail if the output file already exists<\/p>\n notrunc ucase change lower case to upper case<\/p>\n swab swap every pair of input bytes<\/p>\n noerror sync pad every input block with NULs to ibs-size; when used<\/p>\n with block or unblock, pad with spaces rather than NULs<\/p>\n fdatasync physically write output file data before finishing fsync likewise, but also write metadata<\/p>\n Each FLAG symbol may be:<\/p>\n append append mode (makes sense only for output)<\/p>\n direct use direct I\/O for data<\/p>\n dsync use synchronized I\/O for data<\/p>\n sync likewise, but also for metadata<\/p>\n nonblock nofollow noctty do not assign controlling terminal from file<\/p>\n Sending a USR1 signal to a running âddâ process makes it print I\/O statistics to standard error and then resume copying.<\/p>\n $ dd if=\/dev\/zero of=\/dev\/null& pid=$! 18335302+0 records in 18335302+0 records out 9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB\/s<\/p>\n Options are:<\/p>\n –help display this help and exit AUTHOR REPORTING BUGS COPYRIGHT SEE ALSO info dd<\/p>\n should give you access to the complete manual.<\/p>\n dd (coreutils) 5.97 November 2006 DD(1)<\/http><\/bug><\/p>\n#dd if=\/dev\/sdX of=\/tmp\/sda-mbr.bin bs=512 count=1<\/code><\/p>\n#dd if=sda-mbr.bin of=\/dev\/sdX bs=1 count=64
\n skip=446 seek=446<\/code><\/p>\n
\n dd – convert and copy a file<\/p>\n
\n dd [OPERAND]…
\n dd OPTION<\/p>\n
\n Copy a file, converting and formatting according to the operands.<\/p>\n
\n force ibs=BYTES and obs=BYTES<\/p>\n
\n convert BYTES bytes at a time<\/p>\n
\n convert the file as per the comma separated symbol list<\/p>\n
\n copy only BLOCKS input blocks<\/p>\n
\n read BYTES bytes at a time<\/p>\n
\n read from FILE instead of stdin<\/p>\n
\n read as per the comma separated symbol list<\/p>\n
\n write BYTES bytes at a time<\/p>\n
\n write to FILE instead of stdout<\/p>\n
\n write as per the comma separated symbol list<\/p>\n
\n skip BLOCKS obs-sized blocks at start of output<\/p>\n
\n skip BLOCKS ibs-sized blocks at start of input<\/p>\n
\n suppress transfer statistics<\/p>\n
\n 1024*1024, GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y.<\/p>\n
\n replace trailing spaces in cbs-size records with newline<\/p>\n
\n do not create the output file<\/p>\n
\n do not truncate the output file<\/p>\n
\n continue after read errors<\/p>\n
\n use non-blocking I\/O<\/p>\n
\n do not follow symlinks<\/p>\n
\n $ kill -USR1 $pid; sleep 1; kill $pid<\/p>\n
\n –version
\n output version information and exit<\/p>\n
\n Written by Paul Rubin, David MacKenzie, and Stuart Kemp.<\/p>\n
\n Report bugs to
\n Copyright © 2006 Free Software Foundation, Inc.
\n This is free software. You may redistribute copies of it under the terms of the GNU General Public License
\n
\n The full documentation for dd is maintained as a Texinfo manual. If the info and dd programs are properly installed at your site, the
\n command<\/p>\n