Kompx.com or Compmiscellanea.com

Extract tar.bz2

Operating systems : Linux

Extracting tar.bz2 files in Linux, command line:

tar jxvf file.tar.bz2

- j : filter the archive through bzip2 [ 1 ]

- x : extract files from an archive

- v : list the files processed

- f : use archive file

The command extracts the contents of a bzip2 compressed archive to the current directory.

Tar creates an archive of one or several files. Then bzip2 is used to compress it. Or both processes are made at once by tar only, with corresponding options employed. The duality of nature - archived and then compressed - is reflected in the extension of the file ("tar.bz2") and requires two procedures to be performed while extracting: decompressing and unpacking. Hence both j (decompress it) and x (unpack it) in the command.


[ 1 ]

Sources for the option letters description: tar(1) - Linux man page and LinuxCommand.org


Aliosque subditos et thema

 

HTML centering

 

Centering the whole content of a web page in the viewable area of a browser by pure HTML - no CSS. A box to keep the content of the page is HTML centered horizontally and vertically - [ Open demo page ] HTML. Code: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>HTML centering</title> <meta http-equiv="Content-Type" content="text/html; charset=Windows-1252"> </head> <body bgcolor="#ffffff"> <table width="100%" height="100%" bgcolor="#a3ddc4"> <tr> <td align="center"> <table width="800" height="500" bgcolor="#ff6f6f"> <tr> <td>&nbsp;</td> </tr> </table> </td> </tr> </table> </body> </html> The outer HTML table makes the whole web browser viewable area, except margins, a HTML table and the whole area of this HTML table - a HTML table cell. The cell of the outer HTML table inherits the default value for valign attribute from its parent table row. And this row in its turn inherits the default value for valign attribute from the outer HTML table tbody - even if tbody tag is not used. And that value is middle. So a block of content inside the cell of the outer HTML table is centered vertically in web browser viewable are. Align="center" of the outer HTML table cell makes a block of content inside it centered horizontally in web browser viewable are. The inner table, the one inside of the outer HTML table cell makes up a box of a given size. Or there may be no set height or no set width or both. Then the size of the box is to adjust to accommodate the content, whatever its dimensions are. If the width or height or both of the box results to be larger than web browser viewable area, then it still ends up to be centered. Since HTML centering is the oldest method to center content horizontally and vertically, it works well not just in older web browsers, but in ones that can be described as downright ancient. Like adding one more HTML tag ( <center></center> ) around the outer table makes it funcion as deep as Internet Explorer 3 : [ Open demo page ] Download Internet Explorer 3: a pack, containing 3.0, 4.01, 5.01, 5.5, 6.0 versions of Internet Explorer HTML.

Lynx browser. Creating sitemap.xml

 

There are more than few online services for sitemap.xml generation. But it is also possible to do it yourself, by means of lynx web browser and several Linux command line utilities. An example bash script employing them, named "sitemap.sh" is described below. Bash script creating a sitemap.xml file: #!/bin/bash cd /home/me/sitemap/www/ lynx -crawl -traversal -accept_all_cookies -connect_timeout=30 http://www.compmiscellanea.com/ > /dev/null cd /home/me/sitemap/www2/ lynx -crawl -traversal -accept_all_cookies -connect_timeout=30 http://compmiscellanea.com/ > /dev/null cat /home/me/sitemap/www2/traverse.dat >> /home/me/sitemap/www/traverse.dat cat /home/me/sitemap/www/traverse.dat | sed -e 's/\<www\>\.//g' | sort | uniq > /home/me/sitemap/sitemap/sitemap.xml sed -i 's/\&/\&amp\;/g' /home/me/sitemap/sitemap/sitemap.xml sed -i "s/'/\&apos\;/g" /home/me/sitemap/sitemap/sitemap.xml sed -i 's/"/\&quot\;/g' /home/me/sitemap/sitemap/sitemap.xml sed -i 's/>/\&gt\;/g' /home/me/sitemap/sitemap/sitemap.xml sed -i 's/</\&lt\;/g' /home/me/sitemap/sitemap/sitemap.xml sed -i 's/http:\/\//http:\/\/www\./g' /home/me/sitemap/sitemap/sitemap.xml sed -i -e 's/^/<url><loc>/' /home/me/sitemap/sitemap/sitemap.xml sed -i -e 's/$/<\/loc><\/url>/' /home/me/sitemap/sitemap/sitemap.xml sed -i -e '1 i <?xml version="1\.0" encoding="UTF-8"?>\r\r<urlset xmlns="http:\/\/www\.sitemaps\.org\/schemas\/sitemap\/0\.9" xmlns:xsi="http:\/\/www\.w3\.org\/2001\/XMLSchema-instance" xsi:schemaLocation="http:\/\/www\.sitemaps\.org\/schemas\/sitemap\/0\.9 http:\/\/www\.sitemaps\.org\/schemas\/sitemap\/0\.9\/sitemap\.xsd">\r\r<!-- created by sitemap.sh from http:\/\/www.compmiscellanea.com\/en\/lynx-browser-creating-sitemap.xml\.htm -->\r\r' /home/me/sitemap/sitemap/sitemap.xml sed -i -e '$ a \\r</urlset>' /home/me/sitemap/sitemap/sitemap.xml sed -i '/static/d' /home/me/sitemap/sitemap/sitemap.xml echo "...Done" After the bash script file is prepared: "chmod +x sitemap.sh" to make it executable. Download sitemap.sh in sitemap.sh.tar.gz archive ( After downloading and unpacking it, put a web site name with "www" instead of http://www.compmiscellanea.com/ and a web site name without "www" instead of http://compmiscellanea.com/ in the file. Replace "static" in the last line of the file by a string unnecessary links should possess to be removed. Then "chmod +x sitemap.sh". Then run sitemap.sh ). Commentary Download sitemap2.sh with line by line commentary in sitemap2.sh.tar.gz archive. Before running the bash script, three folders should be created. Since lynx browser may miss some links if a web site domain name to be crawled is put with or without "www", bash script runs lynx twice, crawling the web site by its name with "www" and crawling the web site by its name without "www". The two result files are put into two of these separate folders, here they are "/home/me/sitemap/www/" and "/home/me/sitemap/www2/". And "/home/me/sitemap/sitemap/" is for sitemap.xml created in the end. 1. Path to bash: #!/bin/bash 2. Going to a folder - lynx browser is going to put there the files obtained from crawling a web site with "www" in its name: cd /home/me/sitemap/www/ 3. Running lynx browser to crawl a web site.