Readme.howto v1.1 Using wwwgrab is easy. For uncomplicated pages, the URL (location) determines the response from the web server. For example, if you send the web server the right URL, the web server will make a plot or download a file. Figuring the URL is easy as it is displayed on your browser (given the right options.) How browser works (1) browser sends URL to web server (2) web server sends html page to browser (3) browser displays html page How wwwgrab works (1) wwwgrab sends URL to web server (2) web server sends html page to wwwgrab (3) wwwgrab writes the html page to stdout Example 1: Downloading a file by FTP2U Basic steps (1) wwwgrab sends URL to web server (2) web server sends html page to wwwgrab (3) wwwgrab writes the html page to a file (4) script checks the html page for error messages (optional) Steps 1-3 can be done with one line. The hard part is to figure out the URL. Using a browser, finding the URL is cut and paste! Suppose I wanted to download the 1998 Reanalysis monthly PRATE using ftp2u, I do the download by "hand", and on the last page I see the "ftp output:". Netscape shows that the URL for this page as http://sgi62.wwb.noaa.gov:8080/cgi-bin/ftp2u_mf_cdas.sh? file=flx.gau.grib.mean.y98&var_PRATE=on&machine=wesley.wwb.noaa.gov &user=anonymous&passwd=ebis@sgi&ftpdir=%2Fincoming2%2Fwesley&prefix= To download this file, all you have to do is run wwwgrab using the above URL. $ wwwgrab http://sgi62.wwb.noaa.gov:8080/cgi-bin/ftp2u_mf_cdas.sh? file=flx.gau.grib.mean.y98&var_PRATE=on&machine=wesley.wwb.noaa.gov &user=anonymous&passwd=ebis@sgi&ftpdir=%2Fincoming2%2Fwesley&prefix= If you want to check if the transfer was completed, you would have to check the output of wwwgrab. $ wwwgrab http://sgi62.wwb.noaa.gov:8080/cgi-bin/ftp2u_mf_cdas.sh? file=flx.gau.grib.mean.y98&var_PRATE=on&machine=wesley.wwb.noaa.gov &user=anonymous&passwd=ebis@sgi&ftpdir=%2Fincoming2%2Fwesley&prefix= >wwwgrab.output $ count=`grep -c "Transfer complete" wwwgrab.output echo "Transfered $count files" Up to this point, the example has been pretty useless. Why would you want to download a file that you've already downloaded? The trick is that URLs are easy to read. If you changed "file=flx.gau.grib.mean.y98" to "file=flx.gau.grib.mean.y77", then you could download the 1977 PRATE data in a batch script. The only trick is that special characters including the space are replaced by non-special characters. For example, a space is a "+" and a slash is "%2F".