tailieunhanh - 10 Red Hat® Linux™ Tips and Tricks

Are you looking for a quick and simple reference guide to help you navigate Red Hat® Linux™ systems? Look no further! Global Knowledge and Red Hat have assembled these 10 Tips and Tricks from Red Hat Certified Engineers® (RHCEs) to give you an edge on managing these systems. Have you ever needed to completely wipe out critical data from a hard drive? As we all know, mkfs doesn’t erase a lot. (You already knew this, right?) mkfs and its variants (., and mke2fs) only get rid of a few important data structures on the filesystem, but the data is. | Written and Provided by Global Knowledge red hat Expert Reference Series ofWhite Papers 10 Red Hat Linux Tips and Tricks 1-800-COURSES 10 Red Hat Linux Tips and Tricks Compiled by Red Hat Certified Engineers Introduction Are you looking for a quick and simple reference guide to help you navigate Red Hat Linux systems Look no further Global Knowledge and Red Hat have assembled these 10 Tips and Tricks from Red Hat Certified Engineers RHCEs to give you an edge on managing these systems. a Hard Drive By Dominic Duval Red Hat Certified Engineer Have you ever needed to completely wipe out critical data from a hard drive As we all know mkfs doesn t erase a lot. You already knew this right mkfs and its variants . and mke2fs only get rid of a few important data structures on the filesystem but the data is still there For a SCSI disk connected as dev sdb a quick dd if dev sdb strings will let anyone recover text data from a supposedly erased hard drive. Binary data is more complicated to retrieve but the same basic principle applies the data was not completely erased. To make things harder for the bad guys an old trick was to use the dd command as a way to erase a drive. Note This command will erase your disk dd if dev zero of dev sdb There s one problem with this newer more advanced techniques make it possible to retrieve data that were replaced with a bunch of 0s. To make it more difficult if not impossible for the bad guys to read data that was previously stored on a disk Red Hat ships the shred utility as part of the coreutils RPM package. Launching shred on a disk or a partition will write repeatedly 25 times by default to all locations on the disk. Note Be careful with this one too shred dev sdb This is currently known to be a very safe way to delete data from a hard drive before let s say you ship it back to the manufacturer for repair or before you sell it on eBay Copyright 2007 Global Knowledge Training LLC. All rights