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wget overwriting files

Posted on 2011-02-26
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Last Modified: 2012-05-11
I am issuing a wget statement:

wget -c -np -r -N -l inf -w 5 --limit-rate=200K http://www.mysite.com/files

The problem is that it's wasting time downloading files that it already has.  If the files match, I don't want to take the time to download it.
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Question by:hrolsons
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Expert Comment

by:woolmilkporc
ID: 34989146
Hi,

that's a case for timestamping.

Use "-S" for the first download ("preserve timestamps") and "-N" ("newer") for subsequent downloads.

With "-N" ...

... Wget will ask the server for the last-modified date. If the local file has the same timestamp as the server, or a newer one, the remote file will not be re-fetched. However, if the remote file is more recent, Wget will proceed to fetch it.

The above quote is from here:
http://www.gnu.org/software/wget/manual/wget.html#Time_002dStamping-Usage

Good luck!

wmp
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Author Comment

by:hrolsons
ID: 34989201
So, I would change it to :

wget -c -np -r -S -l inf -w 5 --limit-rate=200K http://www.mysite.com/files

for the first, and then:

wget -c -np -r -N -l inf -w 5 --limit-rate=200K http://www.mysite.com/files

Bummer that I have to start this huge download back over again.
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Expert Comment

by:mccracky
ID: 34997534
I don't think so.  From the wget man page:

-N
--timestamping
           Turn on time-stamping.
-S
--server-response
           Print the headers sent by HTTP servers and responses sent by FTP
           servers.

The "-N" already does the timestamping.

What format is the disk filesystem that you are downloading to?  Can it preserve the permissions and timestamps of the original system?  (also, would rsync be an option?)
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Author Comment

by:hrolsons
ID: 34998674
I am downloading to  Windows XP, running GnuWin.

Yes, rsync would be an option.  What would I gain?
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Expert Comment

by:mccracky
ID: 34998991
Is it NTFS or FAT that you are downloading to?
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Author Comment

by:hrolsons
ID: 34999080
NTFS
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Expert Comment

by:mccracky
ID: 34999291
Here is a page talking about the differences between Windows and Linux with respect to timestamps:
http://samba.anu.edu.au/rsync/daylight-savings.html

That might be the problem.  Or that the webserver is not giving out the times (see http://permalink.gmane.org/gmane.comp.web.wget.general/9977)

With rsync you usually use a shell rather than the webserver to download the files so the timestamps might work better.  

If that fails, then with rsync, there is the option "-c" to only compare file checksums rather than time and sizes when doing a transfer.  
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Author Comment

by:hrolsons
ID: 34999375
It seems to be working right now, which makes no sense.  Also, I had to add a trailing backslash to my original command to get it to work right.
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Accepted Solution

by:
hrolsons earned 0 total points
ID: 35186498
It was all about that trailing backslash:

This is incorrect:
wget -c -np -r -N -l inf -w 5 --limit-rate=200K http://www.mysite.com/files

This works:
wget -c -np -r -N -l inf -w 5 --limit-rate=200K http://www.mysite.com/files/
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Author Closing Comment

by:hrolsons
ID: 35221365
It worked
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