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Created by Dr. Xi on March 28, 2011 11:11:33    Last update: March 28, 2011 11:13:21
grep is a versatile command with many variations (grep, egrep, fgrep, then various implementations). It uses a regula expression (regex) pattern to filter input. But then there are basic and extended flavors of regex - leading to even more confusion. And, beware that there are lots of bad examples of regex in the wild... There are two critical questions to ask when you use grep: which grep implementation are you using? what is the flavor of the regex? Here are some examples for gnu grep v2.7: # Find all numbers (no decimal point), basic regex... Use the -o flag to show only the matching part instead of the whole matching line: grep -o -E '\b[0-9]{2}\b' The good thing about the gnu grep is that it...
Created by Dr. Xi on August 30, 2010 20:17:22    Last update: August 30, 2010 20:17:41
Characters \/:*?"<>| are forbidden in Windows file names. For Python, the effect of using a forbidden character in the file name is undetermined. In the following session a file named mytest can be seen from the Windows Explorer, which contains 0 bytes - as confirmed by the read back in the session. But if you open the file with the invalid file name used to create the file (i.e., mytest: 1.txt ), you get the original contents. C:\>python Python 2.7 (r27:82525, Jul 4 2010, ...
Created by voodoo on July 11, 2009 15:14:55    Last update: July 29, 2010 22:45:48
cURL is a command line tool for transferring files with URL syntax. The main purpose and use for cURL is to automate unattended file transfers or sequences of operations. It's really easy to see HTTP headers with curl: C:\>curl --head http://www.google.com HTTP/1.0 ... or, headers and page together (dump headers to stdout): $ curl --dump-header - http://www.google.com HTTP/... Download openssl from openssl.org: curl http://www.openssl.org/source/openssl-0.9.6m.... C:\>curl --help Usage: curl [options...] <url> ...
Created by Dr. Xi on October 23, 2008 03:54:04    Last update: October 23, 2008 03:57:44
Add validator plugin in struts-config.xml <struts-config> . . . ... Set validate="true" on action form <struts-config> <!-- ========== Form Bean De... Add validation rules in validation.xml <?xml version='1.0' encoding='windows-1252'?> <... If you override validate , make sure super.validate is called. package com.example; import javax.servlet.h... Read the documentation: http://struts.apache.org/1.2.4/userGuide/dev_validator.html
Created by Dr. Xi on October 06, 2008 22:48:08    Last update: October 06, 2008 22:50:11
A first attempt would be to create an input file like this: userid password shell_command1 shell_... and feed the lines to the telnet client: cat telnet_input.txt | telnet remote_host #... However, you'll learn soon enough that it doesn't work. You get output like this: Trying 192.168.159.128... Connected to bash... What's happening? The telnet client depleted all input before the remote host had a chance to respond. Since there's no more input, the telnet client initiated to close the connection. Adding a delay between the commands makes it work: (echo userid sleep 10 echo password ... How much time to sleep between commands is just guesswork. You can use Expect to provide more control over the automated session: #!/usr/bin/expect # timeout script aft......
Created by Dr. Xi on October 06, 2008 20:23:49    Last update: October 06, 2008 20:26:45
The __doc__ string on an object provides documentation for the object, which is available from an interactive Python session: $ python Python 2.5.1 (r251:54863, Mar 7 2008,...