regex - 在 RegEx 中将空格转换为制表符

Question

你如何在正则表达式中说以下内容:

foreach line
   look at the beginning of the string and convert every group of 3 spaces to a tab
   Stop once a character other than a space is found

这是我到目前为止:

/^ +/\t/g

但是，这会将每个空格转换为 1 个制表符

任何帮助，将不胜感激。

Answer 1

使用 Perl:

perl -pe '1 while s/\G {3}/\t/gc' input.txt >output.txt

例如，使用以下输入

nada
   three spaces
    four spaces
   three   in the middle
      six space

输出(由 \t 替换的制表符)是

$ perl -pe '1 while s/\G {3}/\t/gc' input | perl -pe 's/\t/\\t/g'
nada
\tthree spaces
\t four spaces
\tthree   in the middle
\t\tsix spaces