Sed
sed 命令成功地在文件中查找和替換，位擦除新文件中的所有內容
我在名為 test2.txt 的文件中有這個 xml 文本
<This is a line of text with a year=2020 month=12 in it This line of text does not have a year or month in it This year=2021 is the current year the current month=1 This is the year=2021 the month=2/> <This is a line of text with a year=33020 month=12 in it This line of text does not have a year or month in it This year=33020 is the current year the current month=1 This is the year=33020 the month=2/>我在文件上執行這個正則表達式：我喜歡commnet第一段，但保留文件的其餘部分
sed -i -En '/./{H;$!d} ; x ; s/<(This.*2020.*)\/>/<!--\1-->/p' test2.txt但結果是 sed 命令刪除了文件中所有其餘的字元串並將正則表達式 init 的結果放入，所以現在 test2.txt 看起來像這樣：
<!--This is a line of text with a year=2020 month=12 in it This line of text does not have a year or month in it This year=2021 is the current year the current month=1 This is the year=2021 the month=2-->如何執行正則表達式但將其他文本保留在文件中？
您明確告訴 sed不要列印，除非該行與模式匹配。因此，只需刪除運算符之後的the
-n和 the ，它就會按您的預期工作：p``s///$ sed -E '/./{H;$!d} ; x ; s/<(This.*2020.*)\/>/<!--\1-->/' file <!--This is a line of text with a year=2020 month=12 in it This line of text does not have a year or month in it This year=2021 is the current year the current month=1 This is the year=2021 the month=2--> <This is a line of text with a year=33020 month=12 in it This line of text does not have a year or month in it This year=33020 is the current year the current month=1 This is the year=33020 the month=2/>但是，這仍然會在開頭添加一個額外的換行符。幸運的是，@Philippos告訴我如何解決這個問題，所以請改用它：
$ sed -E '/./{H;1h;$!d} ; x ; s/<(This.*2020.*)\/>/<!--\1-->/' file <!--This is a line of text with a year=2020 month=12 in it This line of text does not have a year or month in it This year=2021 is the current year the current month=1 This is the year=2021 the month=2--> <This is a line of text with a year=33020 month=12 in it This line of text does not have a year or month in it This year=33020 is the current year the current month=1 This is the year=33020 the month=2/>或者，要編輯原始文件：
sed -i.bak -E '/./{H;1h;$!d} ; x ; s/<(This.*2020.*)\/>/<!--\1-->/' file