仅当找到匹配字符串时才替换行的最后一个单词 [英] Replacing the last word of a line only if match string found

问题描述

仅当找到匹配的字符串时，我才想替换该行的最后一个单词.

I want to replace the last word of the line only if a matching string found.

输入文件:

 "id": 5918915, 

 "description": "Test Job - NA", 

 "revision": 5

预期输出:

 "id": 5918915, 

 "description": "Test Job - EU", 

 "revision": 5

因此，对于匹配 description 的行，用给定的词替换最后一个词.在这种情况下，在第 2 行将最后一个单词 NA", 替换为 EU",

So, for lines matching description, replace the last word with given word. In this case, in line 2 replace last word NA", with EU",

我试过了

sed -i '/"description"/s/.*/EU",//g' file_name

但它不起作用

推荐答案

sed -i -r '/^[ \t]*"description":.*/s/^(.* )NA",[\t ]*$/\1EU/'  FILE

 "id": 5918915, 
 "description": "Test Job - EU",
 "revision": 5"

_{为了测试，移除 -i 开关.}

空白的数量不是很清楚，所以我将 [ \t]* 放置在行首和行尾，用于显示随机大小的空格和制表符.

The amount of whitespace isn't quiet clear, so I placed [ \t]* at line start and end for blanks and tabs of random size.

你的命令:

  sed -i '/"description"/s/.*/EU",//g' file_name

应该用 EU", 替换整行，而不仅仅是最后一个字符序列.

should substitute the whole line with EU",, not just the last char sequence.

-i 是 GNU-sed 的一个选项.检查您的版本并阅读精美的手册.如果您的 sed 缺乏支持，您必须将输出重定向到一个文件 sed "COMMANDS" INFILE >TMP文件；mv TMPFILE INFILE.请注意， sed "COMMANDS" INFILE >INFILE 不起作用，但立即销毁 INFILE；一个流行的、聪明的但功能失调的想法.我也有过.:)

The -i is an option of GNU-sed. Check your version and read the fine manual. If your sed lacks support, you have to redirect the output to a file sed "COMMANDS" INFILE > TMPFILE; mv TMPFILE INFILE. Note, that sed "COMMANDS" INFILE > INFILE will not work, but destroy the INFILE immediately; a popular, clever, but disfunctional idea. I had it too. :)

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