Kinh nghiệm làm việc với Nagios

Plugin NRPE: http://exchange.nagios.org/directory/Addons/Monitoring-Agents/NRPE--2D-Nagios-Remote-Plugin-Executor/details

Lỗi gặp phải khi cài đặt:
- Khi configure NRPE thì có lỗi không tìm được thư viện ssl
- Cách fix: 
+ apt-get install libcurl3-openssl-dev
+ ./configure --with-ssl=/usr/bin/openssl --with-ssl-lib=/usr/lib

Thư mục php-cli

Tìm mãi mới ra. Trong: /usr/bin/php

Trong đó gồm cả thập cẩm mấy thứ: php-ize, php-config....

Regular Expression Wiki

In the BRE syntax, most characters are treated as literals — they match only themselves (e.g., a matches "a"). The exceptions, listed below, are called metacharacters or metasequences.

Metacharacter	Description
.	Matches any single character (many applications exclude newlines, and exactly which characters are considered newlines is flavor-, character-encoding-, and platform-specific, but it is safe to assume that the line feed character is included). Within POSIX bracket expressions, the dot character matches a literal dot. For example, a.c matches "abc", etc., but [a.c] matches only "a", ".", or "c".
[ ]	A bracket expression. Matches a single character that is contained within the brackets. For example, [abc] matches "a", "b", or "c". [a-z] specifies a range which matches any lowercase letter from "a" to "z". These forms can be mixed: [abcx-z] matches "a", "b", "c", "x", "y", or "z", as does [a-cx-z]. The - character is treated as a literal character if it is the last or the first (after the ^) character within the brackets: [abc-], [-abc]. Note that backslash escapes are not allowed. The ] character can be included in a bracket expression if it is the first (after the ^) character: []abc].
[^ ]	Matches a single character that is not contained within the brackets. For example, [^abc] matches any character other than "a", "b", or "c". [^a-z] matches any single character that is not a lowercase letter from "a" to "z". Likewise, literal characters and ranges can be mixed.
^	Matches the starting position within the string. In line-based tools, it matches the starting position of any line.
$	Matches the ending position of the string or the position just before a string-ending newline. In line-based tools, it matches the ending position of any line.
BRE: \( \) ERE: ( )	Defines a marked subexpression. The string matched within the parentheses can be recalled later (see the next entry, \n). A marked subexpression is also called a block or capturing group.
\n	Matches what the nth marked subexpression matched, where n is a digit from 1 to 9. This construct is theoretically irregular and was not adopted in the POSIX ERE syntax. Some tools allow referencing more than nine capturing groups.
*	Matches the preceding element zero or more times. For example, ab*c matches "ac", "abc", "abbbc", etc. [xyz]* matches "", "x", "y", "z", "zx", "zyx", "xyzzy", and so on. \(ab\)* matches "", "ab", "abab", "ababab", and so on.
BRE: \{m,n\} ERE: {m,n}	Matches the preceding element at least m and not more than n times. For example, a\{3,5\} matches only "aaa", "aaaa", and "aaaaa". This is not found in a few older instances of regular expressions.

Examples:

• .at matches any three-character string ending with "at", including "hat", "cat", and "bat".
• [hc]at matches "hat" and "cat".
• [^b]at matches all strings matched by .at except "bat".
• ^[hc]at matches "hat" and "cat", but only at the beginning of the string or line.
• [hc]at$ matches "hat" and "cat", but only at the end of the string or line.
• \[.\] matches any single character surrounded by "[" and "]" since the brackets are escaped, for example: "[a]" and "[b]".

Lỗi khi so sánh chuỗi trong PHP

Mọi hôm lười toàn so sánh kiểu ==

Hôm nay gặp lỗi so sánh 2 chuỗi: 01235000000000000000000000000000001235 &  01235000000000000000000000000000001234  cho kết quả bằng nhau
Giải pháp: chuyển sang strcmp

Sẽ cập nhật sau sự khác nhau giữa strcmp  vs  '=='

Mirror CentOS

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