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This article is about the sample analysis of regular expressions in shell. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Regular expression

Regular expression that matches Chinese characters: [u4e00-u9fa5]

Note: matching Chinese is really a headache. It's easy to have this expression.

Match double-byte characters (including Chinese characters): [^ x00-xff]

Note: can be used to calculate the length of a string (a double-byte character length meter 2 ~ ~ ASCII character counter 1)

Regular expression that matches blank lines: ^ * $

Comment: can be used to delete blank lines

Regular expression that matches the HTML tag:] * >. *? |

Commentary: the version circulated on the Internet is too bad, the above one can only match part of it, and there is still nothing I can do about complex nested tags.

Regular expression that matches the leading and trailing white space characters: ^ s* | slots $

Comment: a very useful expression that can be used to delete white space characters (including spaces, tabs, page feeds, etc.) at the beginning and end of a line

Regular expression that matches the Email address: W + ([- +.] w +) * @ w + ([-.] w +) * .w + ([-.] w +) *

Comment: form validation is very useful

Regular expression that matches the URL URL: [a-zA-z] +: / / [^ s] *

Note: the function of the version circulated on the Internet is very limited, and the above version can basically meet the needs.

Whether the matching account is legal (5-16 bytes are allowed at the beginning of the letter, and alphanumeric underscores are allowed): ^ [a-zA-Z] [a-zA-Z0-9 _] {4j 15} $

Comment: form validation is very useful

Match domestic phone number: d {3}-d {8} | d {4}-d {7}

Commentary: matching forms such as 0511-4405222 or 021-87888822

Match Tencent QQ number: [1-9] [0-9] {4,}

Commentary: Tencent QQ starts from 10000

Match the postcode of China: [1-9] d {5} (?! d)

Commentary: the postal code of China is 6 digits

Match × ×: d {15} | d {18}

Comment: China's xxx is 15 or 18 bits

Match the ip address: dong.dharm.ding.d+

Note: useful when extracting ip addresses

Match specific numbers:

^ [1-9] $/ / match positive integers

^-[1-9] $/ / match negative integers

^ -? [1-9] d _ match $/ / match integer

^ [1-9] d * | 0 $/ / matches a non-negative integer (positive integer + 0)

^-[1-9] d * | 0 $/ / matches non-positive integers (negative integers + 0)

^ [1-9] dquo.d* | 0.d* [1-9] droom$ / / matches positive floating point numbers

^-([1-9] dfol.d* | 0.d* [1-9] d*) $/ / matches negative floating point numbers

^ -? ([1-9] droom.d* | 0.d* [1-9] d* | 0room.0+ | 0) $/ / match floating point number

^ [1-9] dfol.d* | 0.d* [1-9] d* | 0room.0+ | 0 $/ / match non-negative floating point number (positive floating point number + 0)

^ (- ([1-9] dfu.d* | 0.d* [1-9] d*)) | 0room.0+ | 0 $/ / match non-positive floating point number (negative floating point number + 0)

Commentary: useful when dealing with a large amount of data, pay attention to corrections in specific applications

Match a specific string:

^ [A-Za-z] + $/ / matches a string of 26 English letters

^ [Amurz] + $/ / matches a string of 26 English letters in uppercase

^ [amurz] + $/ / matches a string of 26 lowercase letters

^ [A-Za-z0-9] + $/ / matches a string of numbers and 26 letters

^ wrist $/ / matches a string consisting of numbers, 26 letters, or underscores

Thank you for reading! This is the end of this article on "sample Analysis of regular expressions in shell". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it for more people to see!

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