使用sed/awk替换文本文件的一部分 [英] Replace section of text file using sed/awk

问题描述

我正在尝试如下替换#begin和#end之间的文件中的文本:

I'm trying to replace the text in a file between # begin and # end as follows:

# begin

# [block]
# param1=""
# param2=""

# end

读取为:

# begin

[block]
param1="value1"
param2="value2"

# end

基本上，我不会注释[block]行以及它下面的参数值.

Basically, I'm uncommenting the [block] line as well as the param values that fall under it.

推荐答案

使用Mac OS X的BSD sed ¹ :

A simpler solution that avoids unneeded loops, using Mac OS X's BSD sed¹:

/# begin/,/# end/ {    # Search only within this range of text.
  //!s/^# //           # Excluding range borders, delete /^# / from each line.
}

测试:

▶ cat > FILE <<EOF
aaa
bbb
# begin

# [block]
# param1=""
# param2=""

# end
ccc
ddd
EOF

▶ sed -i '' '/# begin/,/# end/{//!s/^# //;}' FILE

▶ cat FILE
aaa
bbb
# begin

[block]
param1=""
param2=""

# end
ccc
ddd

进一步的解释:

• 请注意，空正则表达式//会重复最后一个正则表达式匹配项.因此，//!将其否定.并且/PAT1/,/PAT2/{ //! X }具有将X和/PAT2/都排除在X之外的效果.

• Note that the empty regular expression // repeats the last regular expression match. Thus, //! negates that. And /PAT1/,/PAT2/{ //! X } has the effect of excluding both /PAT1/ and /PAT2/ for X.

¹ 并使用GNU sed进行了测试.

¹ And also tested using GNU sed.

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