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删除特定换行符的Cli命令

command-line-interface sed awk perl

1

Alexander Morland · 技术社区 · 9 年前

```
json :
{
  "something": "here"
}
```

我想解决所有这些问题,使其成为有效的降价,即:

```json
{
  "something": "here"
}
```

如何跨任意数量的文件有效地做到这一点?

我在谷歌上搜索了一下,发现了类似的问题,但无法将它们的解决方案转换为我的特定需求。似乎SED在多行匹配方面并不擅长,而且包含`字符显然也会引起问题。

我试过了

perl -pe "s/\njson :/json/g"

但这并没有给出任何匹配。

1 回复 | 直到 9 年前

1

4

Borodin 9 年前

要使Perl程序工作,需要更改 input record separator $/ . 一个简单的 BEGIN undef 在程序运行其 while 环

$ perl -pe 'BEGIN{undef $/} s/\njson :/json/g' foo
```json
{
  "something": "here"
}

现在,Perl将同时在整个文件中发出咕噜声,这对于降价文档来说应该很好。如果您想处理大小为几GB的文件,请使用更多RAM。

请注意,您需要 -i 也可以进行就地编辑。

$ perl -pi -e '...' *

更简短的版本是使用 -0 标志而不是块来告诉Perl关于输入记录分隔符的信息。 perlrun 这样说:

模式任何大于等于0400的值都会导致Perl将文件整个吞掉, 但按照惯例,0777是通常用于此的值意图

您可以通过使用 re 'debug' pragma ,打开正则表达式的调试模式。它会告诉你的。

$ perl -Mre=debug -pe 's/\njson :/json/g' foo
Compiling REx "\njson :"
Final program:
   1: EXACT <\njson :> (4)
   4: END (0)
anchored "%njson :" at 0 (checking anchored isall) minlen 7 
Matching REx "\njson :" against "```%n"
Regex match can't succeed, so not even tried
```
Matching REx "\njson :" against "json :%n"
Intuit: trying to determine minimum start position...
  Did not find anchored substr "%njson :"...
Match rejected by optimizer
json :
Matching REx "\njson :" against "{%n"
Regex match can't succeed, so not even tried
{
Matching REx "\njson :" against "  %"something%": %"here%"%n"
Intuit: trying to determine minimum start position...
  Did not find anchored substr "%njson :"...
Match rejected by optimizer
  "something": "here"
Matching REx "\njson :" against "}%n"
Regex match can't succeed, so not even tried
}
Matching REx "\njson :" against "```%n"
Regex match can't succeed, so not even tried
```
Matching REx "\njson :" against "%n"
Regex match can't succeed, so not even tried

Freeing REx: "\njson :"

赠品是:

Matching REx "\njson :" against "```%n"
Regex match can't succeed, so not even tried