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 FAQs > Downloading Data
- How to download data:
- Problems during data download:
- How do I download data I purchased?
The specialist who prepared your order should have given you the name of a directory on our server which contains your files. Go to that directory to proceed.
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- How do I get an account on an NCAR computer?
Click here for information on how to request computing resources at NCAR.
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- Can I use Wget to download data files?
You can use Wget to download data files, but you must be a registered data user and you will need to authenticate first to obtain the necessary cookies to include in your wget command. Also, because simultaneous file downloads by a single user degrades the services for other users, you are allowed to download only one file at a time. We monitor our web logs and will block access to users that ignore this rule. Do NOT use the "-b" (or "--background") option on the Wget command line.
NOTE: The ability to post data is not supported in Wget versions prior to 1.9, so you will not be able to download data from us if you are using a Wget version older than that. To see your version of Wget, execute the command "wget -V".
To authenticate, use the following wget command, which you will only need to do once per download session:
wget --save-cookies cookie_file_name --post-data="email=your_email_address&passwd=your_password&action=login" https://dss.ucar.edu/cgi-bin/login
Then, for each file you want to download, load the authentication cookies file as follows:
wget --load-cookies cookie_file_name URL_of_data_file
Since authentication cookies will expire after approximately 24 hours, so you should delete cookie_file_name each time you are done downloading data files and then re-authenticate the next time you want to download more files.
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- Can I use Unix lynx to download data files?
You can use Unix lynx to download data files, but you will need a version that allows you to specify the accept_all_cookies option on the command line and that supports connections to a secure server.
To download a data file interactively, do the following:
prompt>lynx -accept_all_cookies -dump -post_data dss.ucar.edu/cgi-bin/login
stdin>do=login&email=your_email&passwd=your_password&url=url_of_data_file
stdin>---
where:
prompt> is your computer's system prompt
stdin> is the input lynx will need after you execute the command
your_email is the email address that you registered with
your_password is your sign-in password
url_of_data_file is the URL of the data file you want to download
this must begin with a '/' and includes all of the
URL after "dss.ucar.edu"
EXAMPLE:
prompt>lynx -accept_all_cookies -dump -post_data dss.ucar.edu/cgi-bin/login
stdin>do=login&email=dattore@ucar.edu&passwd=*****&url=/datasets/ds824.1/data/n_atl.txt
stdin>---
You can also use lynx within a script. Here is an example Unix shell script (some modifications may be required for other shells) that will download a data file to a local file:
#! /bin/sh
#
# create the input file
cat << ! > input
do=login&email=dattore@ucar.edu&passwd=*****&url=/datasets/ds824.1/data/n_atl.txt
---
!
#
# run the command and direct the output to a file
lynx -accept_all cookies -dump -post_data dss.ucar.edu/cgi-bin/login < input > n_atl.txt
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- How do I download an MSS file to an NCAR computer?
Read about the msrcp command here. For further assistance with retrieving data files from within the NCAR system, please contact the SCD Technical Consulting Group . Include in the subject line something like "moving files between NCAR computers".
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- How do I use SSH to move data from an NCAR computer to my non-NCAR computer?
For assistance moving data to a non-NCAR computer, please contact the SCD Technical Consulting Group, and include in the subject line something like "moving files to a non-NCAR computer".
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- When I click on a data file, my browser displays it. How do I download the file?
To force your browser to download a data file:
- PC users: hold the Shift key at the same time you click the link.
- Mac users: hold the Alt/Option key at the same time you click the link.
Depending on your system, you will either get a pop-up window that allows you to save the file on your computer, or the file will begin downloading immediately.
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- I am trying to download a compressed file (.gz or .Z) and the progress monitor in the download pop-up window is behaving strangely. How do I download the file?
Many browsers know how to handle .gz and .Z compressed files and will uncompress them as they are being downloaded to your computer. Since the browser can't know ahead of time what the uncompressed file size will be, the download progress monitor behaves strangely. For some browsers, it will show the file at 100% downloaded and then it will start over at 0%, doing this several times. Other browsers will show the file 100% downloaded but data are still being transferred. In all cases, as long as data appears to be transferring, you should leave the download process alone until it stops on its own.
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- I downloaded a compressed file (.gz or .Z), but when I try to uncompress it on my computer, I get an error saying that it is not a compressed file. What is wrong?
Many browsers know how to handle .gz and .Z compressed files and will uncompress them as they are being downloaded to your computer. If you get an error when you try to uncompress the file, check the file to make sure it was not uncompressed during the download.
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- Wget complains about certificate verification. What do I do?
If you are using Wget 1.10 or higher, you will need to include the "--no-check-certificate" option on the Wget command line. If you downloaded a script from us with Wget commands, you can add "--no-check-certificate" to the opts variable once and it will apply to all of the Wget commands in the script.
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