echo dot 1 vs 2

I. Single Sign ~ ① In for, the extended variable is used. ② At % var :~ N, m % indicates the string at the specified position using the extended environment variable. ③ Indicates the unary operator in set/a and returns the bitwise inverse of the operand. !① A metaoperator in set/a, indicating non-logical. For example, set/A =! 0, then a indicates logic 1. @① Hide the echo of the command line itself,

restrict a user from accessing this page, you can set the status to 404, as shown below, so that the browser shows that the page does not exist.Header ('HTTP/1.1 404 Not Found ');Header ("status: 404 Not Found ");?> Note: The traditional header must contain one of the following three headers and can only appear once. Content-Type: xxxx/yyyy Location: xxxx: yyyy/zzzz Status: nnn xxxxxx can appear more than twice in the new Multipart MIME Type. Example Example

Php 1. How to determine if the time format is correct: Such as: I need 20110603 such format, this format is the user to fill in, how to determine whether users fill in compliance with this specification,Need code for reference 2. How to determine user logon permissions: such as: After the user logs in, copy an address path to link, set to user cannot access this path, need code reference I hope the gods ar

1 environment Variable Chapter1.1 Modify view effective system environment variables1 files that involve system environment variables---Bash_profile-/etc/profile2 The file location/root/.bash_profile3 file Editor Open VI. bash_profile4 Add to end of fileJava_home =/usr/share/jdk 1.6.0PATH = $JAVA _home/bin: $PATHCLASS _path=. $JAVA _home/lib/dt.jar: $JAVA _home/lib/ Tools.jarexport java_homeexport pathexport CLASSPATH5 file takes effect SOURCE/R

constraint checks must also be completed successfully before this trigger can be executed. If you specify only the FOR keyword, after is the default setting. After triggers cannot be defined on the view. Instead of Specifies that the trigger is executed instead of executing the triggering SQL statement, thus replacing the action of the triggering statement. On a table or view, each insert, UPDATE, or DELETE statement can define a instead of trigger. However, you can define a view on each v

Ec (2); in php, multi-inheritance is not supported. If we use multiple classes to implement code reuse, is there any way? That is the combination. Set another class as an attribute in a class. The following example simulates multiple inheritance. Viewsourceprint? 01 lt ;? Nbsp; 02 classuser { nbsp; 03 nbsp; private $ name quot; tom qu script ec (2 ); script In php, multi-inheritance is not supported.

replacement character", and "target replacement ")Syntax format: $ string = "This is a test ";Echo str_replace ("is", "was", $ string );Echo ereg_replace ("() is", "\ 1was", $ string); \ 1 is to inherit the first wholeEcho ereg_replace ("() is)", "\ 2was", $ string); \ 2 inherits the second wholeSplit () and spliti (c

Ajax Entry Detection User name instance and implementation method We also need a back-end page to determine if the input nickname exists (in this case, for example, PHP tutorial): ... if (isset ($_get[' entryname ')) { $entryname =$_get[' EntryName ']; }else{ $entryname = ' data null '; } $sql =sprintf ("select * from I_test_ajax where nickname= '%s '", $entryname); $res = $iajax->query ($sql); Sleep just to show the effect of readstate==

the shell can often be seen: >/dev/null 2>1 The result of the command can be defined in the form of a%> output /dev/null represents an empty device file where does the > delegate redirect to, for example: echo "123" >/home/123.txt 1 means stdout standard output, the system default is

Code for converting the phpaccess database to the mysql database (12 ). Php Tutorial access database tutorial to mysql tutorial database code "ACCESS database to MYSQL database tutorial" do not understand friends can add QQ: 345838256 php Tutorial access database tutorial to mysql tutorial database code // If you cannot understand the tutorial on converting an ACCESS database to a MYSQL database, you can add QQ: 345838256 ///////////////////////////////// // The data collected by myself is ACCES

-> size. "kb"); // warning if the attachment is exceeded;}} /** Complete file access path **/Function set_file_path (){$ This-> file_path = $ this-> flash_directory. "/". $ this-> datetime. ".". $ this-> extention; // generate the complete file access path;}/** Upload a file **/Function copy_file (){If (copy ($ this-> upfile, $ this-> file_path) {// upload a file;Print $ this-> go_to ("the file has been successfully uploaded! ", $ This-> url); // upload successful;} Else {Print $ this-> showerr

From: http://xierongzhong1.blog.163.com/blog/static/5232328620102921658692/ Shell may often see:>/dev/null 2> 1 Command results can be defined in the form of %> /Dev/null indicates an empty device file. > Indicates the redirection location, for example, Echo "123">/home/123.txt 1 indicates stdout stan

1.for less used to traverse the array of successive numbers subscript, and C language is similar, simple record:for (int $i =0; $i 2.php A foreach statement designed to iterate over an arrayforeach ($arr as $value) {}foreach ($arr as $key = + $value) {}Multidimensional: Using nestedforeach ($arr as $key = + $arr 1) {foreach ($arr

1. how to determine whether the time format is correct 2. how to determine user logon permissions 1. how to determine whether the time format is correct: nbsp; for example, if I need a format like nbsp; 20110603 nbsp;, this format is entered by the user, how to determine whether the user entered meets this specification? nbsp; nbs

[, number step])For example, $ array = range (); indicates array );$ Array = range (a, f); represents array (a, B, c, d, e, f ); Output arrayPhp outputs many array functions, commonly usedBool print_r (mixed expression [, bool return])Void var_dump (mixed expression [, mixed expression [,...])Also, echo, print, and printf can output a single array. 1 2 Http://w

others' programming ideas.9. Develop good programming habits.10. Don't give up when you encounter problems. Be persistent and persistent. PHP configuration is a bit complicated. It was not successfully configured for half a day last night! I have to find a simpler solution: wampserver 5 Integrated Environment Wamp5 is an integrated environment of Apache + PHP + MySql in windows, with simple graphics andMenu installation. This version integrates php5.2.5 mysql5 apache2 phpMyAdmin 2.11.2.1Sql