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Top Forums UNIX for Advanced & Expert Users "Phantom" overwrite with dd on sda*? Post 302921523 by Don Cragun on Friday 17th of October 2014 08:06:15 PM
Old 10-17-2014
It is doing exactly what you told it to do: create a regular file with the literal name /dev/sda* and write zero bytes to that file until the fiesystem containing the /dev directory is out of space.

Shell pathname pattern matching doesn't apply here unless you have a directory in the directory where you run this command with the name of= that contains a directory named dev that contains one or more files that match the pattern sda*. And, if there was more than one file matching that pattern, you would be giving dd two or more of=pathname operands, and that would produce unspecified behavior.

The dd utility can only process one output file per invocation.
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PTARGREP(1)						User Contributed Perl Documentation					       PTARGREP(1)

NAME
ptargrep - Apply pattern matching to the contents of files in a tar archive SYNOPSIS
ptargrep [options] <pattern> <tar file> ... Options: --basename|-b ignore directory paths from archive --ignore-case|-i do case-insensitive pattern matching --list-only|-l list matching filenames rather than extracting matches --verbose|-v write debugging message to STDERR --help|-? detailed help message DESCRIPTION
This utility allows you to apply pattern matching to the contents of files contained in a tar archive. You might use this to identify all files in an archive which contain lines matching the specified pattern and either print out the pathnames or extract the files. The pattern will be used as a Perl regular expression (as opposed to a simple grep regex). Multiple tar archive filenames can be specified - they will each be processed in turn. OPTIONS
--basename (alias -b) When matching files are extracted, ignore the directory path from the archive and write to the current directory using the basename of the file from the archive. Beware: if two matching files in the archive have the same basename, the second file extracted will overwrite the first. --ignore-case (alias -i) Make pattern matching case-insensitive. --list-only (alias -l) Print the pathname of each matching file from the archive to STDOUT. Without this option, the default behaviour is to extract each matching file. --verbose (alias -v) Log debugging info to STDERR. --help (alias -?) Display this documentation. COPYRIGHT
Copyright 2010 Grant McLean <grantm@cpan.org> This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. perl v5.16.3 2013-05-12 PTARGREP(1)
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