Shell and Export commands After the user logs on to the Linux system, a user shell is started. In this shell, you can use shell commands or declare variables, or you can create and run shell script programs. When you run the shell script program,
The PHP parser uses a pair of quotes to judge a string. Therefore, all strings must use the same single or double quotation marks to define the start and end. For example, the following string definition is illegal: 1 The difference between single
First meeting1. Initial knowledgehttp://localhost/Less-1/Prompt for ID, so access http://localhost/Less-1/?id=1Can continue to test the situation of id=2.3.4, etc., will output a different user name and password2. Further informationEach time will
"1" single and double quotation marks when dealing with variables:
Variables enclosed in double quotation marks will interpret the values, but they are not processed in single quotes and are output directly;
"2" If you want to escape in the
About the difference between single and double quotation marks and efficiency issues. A lot of friends understand is not very clear, always thought that single quotation marks and double quotes in PHP are interoperable, until one day, found that
The quote-printable (qP) method is usually abbreviated as "Q". The principle isThe 8-bit character is represented by two hexadecimal values, and "=" is added to the front ". So we can see that it is encoded by QP.The following file is usually like
1. Define String
In PHP, a string can be defined using single quotes or double quotes. However, you must use the same single or double quotes to define the string, such as: ' Hello ' and ' hello ' are illegal string definitions.
When you define
The difference between single quotation marks and double quotes in PHP
In a programming language, both single and double quotes are important, as is the case in the PHP language. Compared to ASP, PHP quotation marks better use, in ASP, to put the
1. Defining Strings
In PHP, the definition of a string can use either single quotation marks or double quotes. However, you must use the same single or double quotation marks to define strings, such as: ' Hello ' and ' hello ' are illegal
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