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Created by jinx on April 28, 2011 21:09:08    Last update: April 28, 2011 21:09:08
PHP global variables are defined outside of functions and classes. They are visible both in the current file and in any included/required files. Also, any global variables defined in required/included files are visible in the current file. But they are not visible in any functions or classes, unless specifically declared global . Test: Create file test.php : <?php ini_set('display_errors', 'stderr'); i... Create file test.inc : <?php echo '[', __FILE__, '] $a . $b = ', $... Run the PHP script in command line: php test.php 2>C:\tmp\stderr.out The result is: [C:\work\test.inc] $a . $b = ab [C:\work\test.p... stderr messages: PHP Notice: Undefined variable: b in C:\work\scra...
Created by Dr. Xi on February 09, 2011 13:27:51    Last update: February 09, 2011 13:27:51
By the perldoc , use Module LIST; is exactly equivalent to: BEGIN { require Module; Module->import( LIST); } Because of the BEGIN block, use is executed immediately. Therefore, it is not suitable for lazy loading of modules at runtime. use does not work with a runtime variable: C:\>perl $cgi = "CGI"; require $cgi; prin... require works: C:\>perl $cgi = 'CGI'; require "${cgi}.pm"; ... Also, file extension is required if require is not passed a bareword: // this works require CGI; // so does th...
Created by Dr. Xi on January 04, 2010 05:04:10    Last update: January 07, 2010 15:59:25
This is the error: >>> import urllib2 >>> f = urllib2.urlopen('htt... Reason: SSL is not supported in Python installation. >>> import httplib >>> hasattr(httplib, 'HTTPS'... Solution: recompile Python with SSL on Steps: Download and install OpenSSL , if you don't have it already. Download Python source and rebuild Python (the usual steps of configure, make and make install). Python's configure script should be able to pick up your existing SSL libraries automatically and build a shared library _ssl.so. Some web sites suggest editing the file Modules/setup.dist , uncomment the lines starting with _ssl , and making changes to the SSL path. This would link the SSL library statically to Python. # Socket module helper for socket(2) #_socket s...
Created by Dr. Xi on December 05, 2009 20:12:16    Last update: December 05, 2009 20:46:45
It's quite easy for Perl to open a pipe and read from it: $file = "nospace.txt"; open(IN, "cat $file |") ... But the code breaks when the file name contains a space: # This does not work! $file = "yes space.txt"; ... On Windows, these don't work either: # This does not work! $file = "yes space.txt"; ... You need to use a technique called Safe Pipe Opens : $file = "yes space.txt"; $prog = "cat"; ...
Created by Dr. Xi on December 04, 2009 04:33:05    Last update: December 04, 2009 04:33:05
Variable Meaning $_ The default or implicit variable. @_ Within a subroutine the array @_ contains the parameters passed to that subroutine. $a, $b Special package variables when using sort() $<digit> Contains the subpattern from the corresponding set of capturing parentheses from the last pattern match, not counting patterns matched in nested blocks that have been exited already. $. Current line number for the last filehandle accessed. $/ The input record separator, newline by default. $| If set to nonzero, forces a flush right away and after every write or print on the currently selected output channel. Default is 0 (regardless of whether the channel is really buffered by the system or not; $| tells you only whether you've asked Perl explicitly to flush after...
Created by Dr. Xi on December 14, 2008 19:09:19    Last update: December 14, 2008 19:09:19
My mod_python app failed to extract Python eggs with this error: [Sun Dec 14 09:40:03 2008] [error] [client 127.0... The error message suggested to set the PYTHON_EGG_CACHE environment variable. While this may help solve the problem, there's no reason why the Python egg can't be installed expanded: easy_install -Z MySQL-python-1.2.2.tar.gz
Created by Dr. Xi on September 29, 2008 23:05:12    Last update: September 29, 2008 23:06:16
These variables are set or used by the Unix shell to modify its behavior. Variable Description ENV=file Name of script that gets executed at startup; Usually, ENV=$HOME/.kshrc FCEDIT=file Editor used by fc (fix command) command. If $FCEDIT is not defined, use $EDITOR, otherwise use the default (vi or ed). FPATH=dirs Directories to search for function definitions; undefined functions are set via typeset -fu . FPATH is searched when these functions are first referenced. HISTFILE=file File in which to store command history. Default is $HOME/.sh_history for Korn shell, $HOME/.bash_history for Bash. If not set, history is lost after logout. HISTSIZE=n Max number of commands to keep in history. HOME=dir Home directory; set by login from passwd file. IFS='chars' Internal field separators. Default is space, tab, and...
Created by Dr. Xi on September 23, 2008 20:43:58    Last update: September 23, 2008 20:43:58
Variable Description $0 The name of the ruby script file $* The command line arguments $$ Ruby interpreter's process ID $? Exit status of last executed child process $_ String last read by gets $. Line number last read by interpreter $! Last error message $@ Location of error $& String last matched by regexp $~ The last regexp match, as an array of subexpressions $n the nth subexpression in the last match (same as $~ ) $= Sase-insensitivity flag $/ Input record separator $\ Output record separator
Created by Dr. Xi on April 26, 2007 03:17:14    Last update: May 05, 2007 19:50:26
To loop through an envionment variable: @echo off set a=1 2 3 for %%i in (%a%) d... To loop through the command line arguments: @echo off for %%i in (%*) do echo %%i