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authorJim Meyering <jim@meyering.net>2001-04-29 07:01:41 +0000
committerJim Meyering <jim@meyering.net>2001-04-29 07:01:41 +0000
commit6b647033ceb0d6170332bd67207ea460e2de8297 (patch)
tree8b9060dea6ddb860fa7b88dc9c44cb9f74310c43 /src
parentc8576c4f8c67393ba0545c160c61d28b3b0c2f6d (diff)
downloadcoreutils-6b647033ceb0d6170332bd67207ea460e2de8297.tar.xz
(usage): Include in --help output the warning about
some of the filesystem types on which shred is not effective.
Diffstat (limited to 'src')
-rw-r--r--src/shred.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/src/shred.c b/src/shred.c
index 21469176e..152c303ab 100644
--- a/src/shred.c
+++ b/src/shred.c
@@ -482,6 +482,25 @@ Delete FILE(s) if --remove (-u) is specified. The default is not to remove\n\
the files because it is common to operate on device files like /dev/hda,\n\
and those files usually should not be removed. When operating on regular\n\
files, most people use the --remove option.\n\
+\n\
+CAUTION: Note that shred relies on a very important assumption:\n\
+that the filesystem overwrites data in place. This is the traditional\n\
+way to do things, but many modern filesystem designs do not satisfy this\n\
+assumption. The following are examples of filesystems on which shred is\n\
+not effective:\n\
+\n\
+* Log-structured or journaled filesystems, such as those supplied with\n\
+ AIX and Solaris (and JFS, ReiserFS, XFS, etc.).\n\
+\n\
+* Filesystems that write redundant data and carry on even if some writes\n\
+ fail, such as RAID-based filesystems.\n\
+\n\
+* Filesystems that make snapshots, such as Network Appliance's NFS server.\n\
+\n\
+* Filesystems that cache in temporary locations, such as NFS\n\
+ version 3 clients.\n\
+\n\
+* Compressed filesystems.\n\
"), DEFAULT_PASSES);
puts (_("\nReport bugs to <bug-fileutils@gnu.org>."));
}