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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/coreutils.texi | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 9c3e2ed67..8a1b3b62c 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -8892,6 +8892,20 @@ your hard disk, you could give a command like this: shred --verbose /dev/sda5 @end example +On modern disks, a single pass should be adequate, +and it will take one third the time of the default three-pass approach. + +@example +# 1 pass, write pseudo-random data; 3x faster than the default +shred --verbose -n1 /dev/sda5 +@end example + +To be on the safe side, use at least one pass that overwrites using +pseudo-random data. I.e., don't be tempted to use @samp{-n0 --zero}, +in case some disk controller optimizes the process of writing blocks +of all zeros, and thereby does not clear all bytes in a block. +Some SSDs may do just that. + A @var{file} of @samp{-} denotes standard output. The intended use of this is to shred a removed temporary file. For example: |