question

optimize markdown documents with sed

introduce

You are the document inspector of the shiyanlou, need to check document format every day, a document found in different marks appear blank between too much (provisions require only a blank document appeared in 2, 3 cases), and all the image formats are written into the link, need you use this document to quickly repair Sed.

For example, a document does not regulate instances and link errors:

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## title one

## Title Two



## Title Three

[picture-1] (https://www.shiyanlou.com/test.png)

Title Two and Title Three require only one empty line directly.

you should execute the Sed script in this way:

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Sed -f /home/shiyanlou/fix-format.sed document

After execution, the document is turned into:

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## title one

## Title Two

## Title Three

[picture-1] (https://www.shiyanlou.com/test.png)

target

  1. The script path must be placed in the /home/shiyanlou/fix-format.sed
  2. The way to call is: sed -f /home/shiyanlou/fix-format.sed document
  3. Delete extra repeat blank lines in a document
  4. revising the format of the picture link

Hint

  1. sed matching empty lines

  2. the hints of the picture link are all in [picture-xxx] format, and the suffix of the address is.Png or.Jpg

  3. test document download link: http://labfile.oss.aliyuncs.com/courses/980/test-document.md

Knowledge point

  • regular expression
  • Sed

keypoint

  • delete rows retain only one line

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    /^$/{
      N
      /^\n$/D
    }

  • replace

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    s/\[picture/\!\[picture/

Note that the escape character

references