rbj@icst-cmr.arpa (Root Boy Jim) (04/27/88)
From: Dennis John Linse <djlinse@phoenix.Princeton.EDU>
Last night I was trying to figure out how to due an incremental backup
on a Silicon Graphics Iris running System V. The manual suggested using
find . -mtime -7 -print | tar c -
The problem I encountered was that the find command finds all of the
directories along the way. For example the output of find might be
./bin
./bin/foo
where foo is a file to be backed up. When tar gets this, it recursively
backs up the entire bin directory. After much work, I came up with the
command
find . \( -mtime -7 -exec test -f {} \; -print \) | tar c -
which seems to due the trick.
Right idea, but see below.
The questions I have are
1) Is this the best way or is there a better one?
Replace "-exec test -f {} \;" with "-type f".
2) Does the resulting archive have the necessary directory information
to recreate the files in the event that they are needed?
Specifically, if a directory doesn't exist when the archive is read
back in, will it be created properly?
Yes. Tar creates directorys, but does not restore their modification
time correctly. Additionally, the owner/group/mode will not necessarily
be set correctly if the directory does not exist when restoring it.
Additionally, symbolic links may give you trouble. Perhaps you might
want "! -type d" instead of "-type f".
You may also want to add a "| fgrep -v -f filesnotosave |" between the
find and the tar.
Dennis
(Root Boy) Jim Cottrell <rbj@icst-cmr.arpa>
National Bureau of Standards
Flamer's Hotline: (301) 975-5688
The opinions expressed are solely my own
and do not reflect NBS policy or agreement
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