In a shell script written by OPS, it is sometimes necessary to put some content directly into a file, such as configuring some content in a shell script to regenerate into a shell script, using the cat command and redirect symbol "#!/bin/sh#thescriptisinstallnginx#echo "Addusermars" #groupadd xiaoyaouseradd-gxiaoyaoxiaoyaosed-i ' s/\ #PermitRootLogin yes/permitrootloginno/g ' /etc/ssh/sshd_configservice sshdrestartpasswdxiaoyaoecho "Configuresysctl"
I. The problem arisesToday to see Ali's pen test, see a very interesting topic, but it is easy to make mistakes. Title: The following function, the value of the 32bit system foo (2^31-3) is:int foo (int x) {return x-x;} Answer: If you want to correct this problem, first of all to understand the C language of the priority level of the symbol, minus (-) the priority is higher than ^, so 2^31-3=2^28, there is a trap is C language that ^ is an XOR opera
"This article from the public number" Deng takes you to play Python ", reproduced"Import mathmath.sqrt (8)2.8284271247461903Let's look at the results in PythonMATH.SQRT (8). MATH.SQRT (8)8.000000000000002Ben thought it would get 8.0, but didn't expect to get 8.000000000000002.First, why is this?If our usual tasks often have expressions similar to those in the example above, then directly using Python to calculate the result is just an approximation of the real value. If this is a lot of calculat
XSS prevents attacks where a malicious user executes the input information as HTML or JS code by changing the information entered by the user into text format, or special symbol escapingPrevention of XSS attackThe harm caused by XSS attacks occurs because the user's input becomes executable code, so we are going to HTML-escape the user's input by escaping the special characters, such as angle brackets, quotation marks, single quotation marks, and so o
variable content of $b, by changing the value of $ A in the function can change the value of $becho "echo $b;//Output 101?>It is important to note that here Test (1), the words will be wrong, reason to think.Attention:The "test" above ($b); Do not add the symbol in front of the $b, but in the function "call_user_func_array", to reference the arguments, you need the symbol, as shown in the following code:
Why to use an escape string.
This is going to be about the HTML escape string (Escape Sequence).
An escape string (Escape Sequence) is also called a character entity (Character Entity). There are two reasons to define an escape string in HTML: The first reason is that symbols such as "the composition of the escape string
The Escape string (Escape Sequence), that is, the character entity (Character Entity) is divided into three parts: the first part is a
string class with the "'", asCondition = "Name= '" +tempname. Replace ("" "," "") + ""
B. DateYou can use the # symbol to process queries in ado.net that involve date formats, as shown in the following exampleCondition = "enddateC. Column SeparatorWhen a column in a datasheet contains a column separator for some reason, such as sale order, you can use [] to differentiate this column, as shown in the following examplecondition = "[Sale order] = S84564
write triangle as the Triangle property of the ShapeType object, thus eliminating strong coupling.
If you analyze carefully, you can see that shapetype.triangle equals which value is not important, just make sure that it does not conflict with the values of other ShapeType properties. Therefore, this is a good place to switch to Symbol values.
Const SHAPETYPE = {
triangle:symbol ()
};
The above code, in addition to setting the value of Shapetype.
Preface
Symbol table, a kind of mapping relation, realizes the commonly used hash table concretely. In many cases, real-world things can not be represented in the computer, this time need symbol table, it gives us to build the real world and the computer World Bridge. comparison of common methods
Method
Average insertion Time
average time to find
avg. Delete Time
L
Tags: linker resolution. com setting NEC Summary debug Scenario ErrorFirst, the general Error: DESKTOP/PROJECT/ASDF/WEIXIN/LIBWECHATSDK.A (3 slices) Undefinedsymbols for architecture arm64: Such a compilation problem really good headache, the following is a useful way. Archs = ARMv7 armv7s Valid_archs = armv6 armv7 armv7s arm64 Second, http://stackoverflow.com/questions/33321897/xcode-7-1-symbols-not-found-for-architecture-arm64 Xcode 7.1-symbol (s)
security considerations include the $ special symbol when setting up the MySQL password, which causes the following error to run when writing the script:After some toss found the original is $ led to the decisive change password, as for the reasons themselves Baidu to find me here does not explain the method of changing the password as follows:Method 1: Use the Set password commandFirst log in to MySQL.Format:mysql> set password for user name @localho
Tags: code font into NTPD password values write code SQL databaseYesterday began to write code, the data inserted into the MySQL database, but there is no way to insert, Internet search, the final method is to insert the data in the phpMyAdmin after the conversion to PHP statements, and finally the following:$sql = "INSERT into ' stu ' (' Sno ', ' sname ', ' Password ', ' parentpd ', ' ssex ', ' cid ', ' cname ', ' gid ', ' grade ', ' Syid ', ' Sye ') Ar ', ' group ', ' Groupleader ', ' post ',
# Well No. (comments)#管理员 $ ordinary User
In the script
#!/bin/bash #!/bin/sh
Typically appear in the first line of the shell script, meaning to use/bin/bash to execute the current shell script, except for the first line, which plays the role of annotation. (in the shell script)
Well numbers often appear at the beginning of a line, or after a complete instruction, which indicates that the symbol is followed by the callout text and is not executed.
# T
First to install the plugin, the plugin download address is: Http://www.wps.cn/index.php?mod=addonsact=frontSearch
Click "Download Now" in the diagram to automatically open a WPS text document, pop-up "Office gadgets" dialog box, will soon be under the "Plugin download" tab under the Prompt installation success, click the "Close" button, close the Office Gadgets dialog box.
When the enhanced symbol Bar plug-in is installed, a
the simplest way to quickly enter the diameter symbol φ
1, the simplest and most reliable method: Save this Web page, each time you use this web site, and then copy the diameter symbol φ and paste into the document.
2, hold down the keyboard "ALT" key, and then continue to press the keypad number 42677, and finally press the ALT key released, you can get a (Φ) diameter
It is very difficult for WinDBG to load the symbol table. It is clear that the path of the symbol table has been loaded, but the breakpoint cannot be added. The following is the subject:
The symbol table cannot be loaded and the breakpoint cannot be triggered.
1. Check whether sympath is correct
Kd>. sympathSymbol search path is: srv * SignatureExpanded
Http://blog.chinaunix.net/uid-20543672-id-3023148.html
A few days ago a colleague asked me: If a module to call the function of another module, do not do anything special processing. I just knew I needed to be called the function Export_symbol ();. However, because of the specific module experiment has not done, I immediately made a show to him, I also verified. As soon as the experiment was done, the problem came: though the compilation passed (with a warning:WARNING:"Exported_function_2" [/ho
Create a new environment variable _NT_SYMBOL_PATH value is: srv*c:\mysymbol* http://msdl.microsoft.com/download/symbols
WinDbg unable to load symbol table is very painful things, clearly the symbol table path has been loaded, but still can not add breakpoints, the following directly into the theme:The symbol table cannot be loaded and the breakpoint cannot be tri
Ver2.0:
struct Node:Std::unique_ptrstd::string name; Node nameStd::vectorStd::shared_ptrStd::unique_ptrClass Description:1 each node corresponds to a symbol in Python, the variable symbol/action symbol2 operation symbol should contain operation function, input symbol, output symbol
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