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SHRED |
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!!!SHRED |
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NAME |
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SYNOPSIS |
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DESCRIPTION |
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AUTHOR |
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REPORTING BUGS |
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COPYRIGHT |
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SEE ALSO |
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---- |
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!!NAME |
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shred - delete a file securely, first overwriting it to hide its contents |
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!!SYNOPSIS |
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__shred__ [[''OPTIONS''] ''FILE'' [[...] |
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!!DESCRIPTION |
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Overwrite the specified FILE(s) repeatedly, in order to make |
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it harder for even very expensive hardware probing to |
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recover the data. |
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__-f__, __--force__ |
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change permissions to allow writing if |
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necessary |
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__-n__, __--iterations__=''N'' |
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Overwrite N times instead of the default (25) |
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__-s__, __--size__=''N'' |
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shred this many bytes (suffixes like k, M, G |
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accepted) |
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__-u__, __--remove__ |
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truncate and remove file after overwriting |
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__-v__, __--verbose__ |
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show progress |
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__-x__, __--exact__ |
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do not round file sizes up to the next full |
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block |
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__-z__, __--zero__ |
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add a final overwrite with zeros to hide |
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shredding |
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- |
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shred standard output |
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__--help__ |
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display this help and exit |
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__--version__ |
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print version information and exit |
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Delete FILE(s) if __--remove__ (-u) is specified. The |
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default is not to remove the files because it is common to |
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operate on device files like /dev/hda, and those files |
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usually should not be removed. When operating on regular |
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files, most people use the __--remove__ |
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option. |
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CAUTION: Note that shred relies on a very important |
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assumption: that the filesystem overwrites data in place. |
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This is the traditional way to do things, but many modern |
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filesystem designs do not satisfy this assumption. The |
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following are examples of filesystems on which shred is not |
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effective: |
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* log-structured or journaled filesystems, such as those |
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supplied with |
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AIX and Solaris (and JFS, ReiserFS, XFS, etc.) |
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* filesystems that write redundant data and carry on even if |
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some writes |
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fail, such as RAID-based filesystems |
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* filesystems that make snapshots, such as Network |
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Appliance's NFS server |
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* filesystems that cache in temporary locations, such as |
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NFS |
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version 3 clients |
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* compressed filesystems |
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!!AUTHOR |
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Written by Colin Plumb. |
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!!REPORTING BUGS |
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Report bugs to |
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!!COPYRIGHT |
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Copyright 2001 Free Software Foundation, Inc. |
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This is free software; see the source for copying |
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conditions. There is NO warranty; not even for |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR |
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PURPOSE. |
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!!SEE ALSO |
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The full documentation for __shred__ is maintained as a |
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Texinfo manual. If the __info__ and __shred__ programs |
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are properly installed at your site, the |
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command |
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__info shred__ |
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should give you access to the complete manual. |
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---- |