1zidrav(1)                                                            zidrav(1)
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NAME

6       zidrav - detect and repair corruption in transfered files
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SYNOPSIS

9       zidrav [-b bs] [-o CDT] corrupted file
10       zidrav -p [-i CDT] [-o CDP] original file
11       zidrav -a [-i CDP] corrupted file
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DESCRIPTION

14       zidrav  is  a  file  corruption  detection  and  repair  program.  It's
15       designed to provide a way to fix file damage without having to  redown‐
16       load the entire (potentially large) file over a (potentially slow) con‐
17       nection.
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19       There are 3 steps to using zidrav (in the order of  the  SYNOPSIS  com‐
20       mands):
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22              1.  Create a checksum file of the corrupted file.
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24              2.  Using the checksum file, create a patch file from the origi‐
25              nal file.
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27              3.  Apply the patch file to the corrupted file.
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29       At each of the steps, the checksum or patch file has to be in the  same
30       directory  as  the  corrupted or original file, depending on which step
31       you're on, unless otherwise specified with -i.
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OPTIONS

34       -a     Apply the patch file to the corrupted file in order to fix it.
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36       -b     Set the blocksize.  The default blocksize it 16384.
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38       -h     Show usage summary and exit.
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40       -i     Specify the input filename of the checksum (CDT) or patch  (CDP)
41              files.   You  have  to  use  this  flag when the basename of the
42              checksum or patch files doesn't match the name of  the  original
43              file.
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45       -o     Specify an output filename for the checksum (CDT) or patch (CDP)
46              files.  By default, the name of original file  is  used  as  the
47              basename for these files.
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49       -p     Build the patch file from the original file.
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51       -V     Display version information and exit.
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EXAMPLE

54       In  this  example,  let's  assume  you've downloaded a large file named
55       freebsd4.8.iso from a remote ftp which you have shell access  to.   The
56       file  was  corrupted  during transfer and you need to use zidrav to fix
57       the file.
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59       First, build a checksum file from the corrupted file on your machine:
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61              zidrav freebsd4.8.iso
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63       This creates a checksum file named freebsd.4.8.iso.cdt.
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65       Next, transfer the checksum file to the remote ftp computer in the same
66       directory as the original file.  From that directory, type:
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68              zidrav -p freebsd.4.8.iso
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70       This creates a patch file named freebsd.4.8.iso.cdp.
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72       Last, transfer the patch file back to your computer, in the same direc‐
73       tory as the corrupted file.  From that directory, type:
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75              zidrav -a freebsd.4.8.iso
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77       This will apply the patch and fix the corrupted file.
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BUGS

80       The corrupted file has to be equal in size as the original file.   This
81       makes  it  so  you  can't  fix partially downloaded files until they're
82       padded.
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AUTHOR

85       zidrav is written by Zorba <zorbathut@uswest.net>.  Unix port was  done
86       by  Piotr  Krukowiecki {piotr at krukowiecki dot net}.  This manpage by
87       Cosmin Stroe <cstroe1@uic.edu>.
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91                                 July 14, 2003                       zidrav(1)