Release date:Updated on: 2012-03-13
Affected Systems:Debian Linux 6.0 xCpan yaml-LibYAML 0.38Cpan yaml-LibYAML 0.33-1Description:--------------------------------------------------------------------------------Bugtraq id: 52381Cve id: CVE-2012-1152
Perl is a high-level, general, literal, and dynamic programming language.
The Perl YAML-LibYAML module has multiple format string vulnerabilities. Attackers ca
, commaIs the function of a connection: $a +=1, $b = $a; ==> $a +=1; $b = $a;No eggs.Eight, conditional operatorsThree operands: evaluates the conditional expression first, and executes the question mark (? The following operation, which executes a colon when false (:) After the operation.$result = $var = = 0? 14:7 #一般只用于简单的条件 too complex is not as good as if statement looks intuitiveIx. Precedence of operators (precedence)Self-increment self-reduction highest, single operand higher than multi-o
Preface
Sometimes there are these requirements:
1. count the number of rows of a file
2. Calculate the number of valid lines of a source code. Exclude empty and comment rows
3. Unify the quantity and number of files in a directory
Many languages can achieve these needs, but using Perl should be a good choice.
Number of lines reading files
It's easy to use Perl to read the total number of lines in a file (
This article focuses on the concept of Perl variables in the Perl syntax, where Perl variables are divided into scalar variables, array variables, and relational array variable 3 classes. Perl's variables are sensitive to size, such as: An,an,an is a 3-divided variable, but a variant of a different paradigm can use a uniform name.
Introduction to
1.PERL4 Kinds of variablesScalar: $ pure variable, scalarArray: @Hash:%File: Uppercase2. Variable composition1. Naming rules case sensitive, alphanumeric underline ...2. No keywords, $+ other, but can not conflict with built-in variables.3. The name length is infinite.3. In pure variables: integer, float, character, string,Integer variable1. You can use _ to divide character numbers2.012 is octal 103.0X1F is 16 binaryFloating-point variable1.11.42.-0.33..3can represent a 15-bit valid number, tru
1. Module source: Pack and download from CPAN together with the Perl release version
2. Read the module documentation: perldoc CGI
3. Installation Module
Makemaker mode:
Specify the installation directory:
Module: Build mode:
CPAN method:
4. File: basename Module
5. Select only some functions of the module.
Import the reference list.
10. Do not introduce any function
Use the full name:
11. File: spec Module
12. cgi.
Reference: http://shouce.jb51.net/perl5/Web site environment configuration: http://www.jb51.net/article/74005.htm
The basic syntax of Perl http://www.jb51.net/shouce/Perl.htm
Preface: What is Perl, and what is it used for? Perl's original designer's intention was to handle characters, and 80% of the strength was to handle characters, of course, many others. Many web pages are now
When you're learning Perl, it's hard to care if Perl is obsolete. Is this version already obsolete?
For the previous question, it may be useful to refer to the February 2012 Tiobe report, according to which we can see that Perl has been a downward trend since 1997, but we can also see that Perl has been in the top 10
Which platforms have Perl on? Where are we going to find them?
The standard release of Perl (maintained by the Perl Development Group) is distributed only in the original code form. You can obtain it at http://www.perl.com/cpan/src/latest.tar.gz. The format of this file is the POSIX tar filing cabinet, which is then compressed in gzip format. This source code ca
Practical Extraction and Report Language
Perl was originally designed by Larry Wall in December 18, 1987. Perl uses the features of C, sed, awk, shell scripting, and many other programming languages.
Perl is generally called the Practical Extraction and report language, although it is sometimes called the pathologicallyeclectic rubbish Lister ). It is the term,
Author: hoowa Source: AKA magazine
"How did Larry Wall invent a messy programming language-and then changed the Web landscape? "
Larrywall smiled and recalled the message that David Filo, the co-founder of Yahoo, sent to him a few years ago, shortly before Yahoo was publicly available. file wrote: "Without Perl, the general programming language invented by wall, Yahoo cannot begin. so, Larry, are you willing to buy some cheap, Yahoo's original stock
Enable Perl before compiling Vim;
Use the Perl interface ** Perl-using **: Perl **: Pe *: PE [RL]{cmd}Run the Perl Command{cmd}. The current package is "Main ". : PE [RL] {endpattern}{script}{endpattern}Execute the Perl script{s
What is Perl?
Perl is a high-level programming language, written by Larry Wall and many others, and incorporates the characteristics of many languages. It is mainly by the ubiquitous C language, followed by the SED, Awk,unix shell and at least a dozen other tools and languages evolved. Perl for process, files, and text has a very strong processing and transforma
I. Data Types(Data type):
Perl has four data types: Scalar (variable), Scalar Array (Array), Hash Array (Hash), and References (pointer ), it seems to be rare, but it is more than enough to use it. Especially when writing Perl programs, you do not need to declare variables in advance. This is very convenient for those who are new to programming languages. However, in order to facilitate program debugging a
one. DataType (data type ):
Perl's data types are roughly four: Scalar (variables), Scalar Array (array), hash array (hash), References (pointer), but they seem to be small but more than sufficient. In particular, you can write a Perl program without the prior declaration of variables, this is very convenient to learn the language of the program, but in order to later debugging and maintenance convenience, I suggest you or form the habit of declaring
How to Use eclipse to debug a Perl application before 11:30:36
This tutorial will introduce the debugging functions provided by the eclipse epic plug-in. This plug-in provides a rich debugging environment that can be used in the epic Perl development environment and integrated with this development environment. This tutorial assumes that you understand the eclipse environment and have experience using
The concept of the Perl method in the Perl language do you know, here's a quick introduction to Perl's perl approach as a Perl subroutine, or a commonly called member function.
Perl method
A brief introduction of Perl method
Interactive publishing network computer channel. A book tutorial for you on the Perl language is recommended. Includes Perl push, Perl Chomp, and Perl python content.perl language book One, "Perl Language Programming fourth edition (in the book) (Photocopy version)"
Reference
Common Perl Command Line options
Common unix Commands: perl implements sed awk tr nl
Perl, sed, awk, tr, grep, nl, and other common commandsSed
Task
Sed
Perl
Replace12WithTwelve
sed 's/12/twelve/g'
perl -pe 's/12/twelve/g'
Re
Http://www.mdbbs.org/thread-28471-1-1.html This is a reference method when I learn Perl, I feel very good, share with you:
Each person has different learning methods. The following are some examples for your reference.
If Perl is the first programming language you have learned, we recommend that you first read some programming basics, process control, logic, and design knowledge. _ Do you have any good C
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