Bash:使用参数扩展查找和替换 [英] Bash: Find and replace using Parameter Expansion

问题描述

我要替换输入，

find_string:@include circle-progress(38px，30px，#4eb630)

find_string: @include circle-progress(38px, 30px, #4eb630)

并输出

Output_string:@include circle-progress(38px，30px)

Output_string: @include circle-progress(38px, 30px)

使用 $ {find_string//pattern/replacement_string} ，其中pattern是，，#[A-Fa-f0-9] [A-Fa-f0-9] [A-Fa-f0-9]?([A-Fa-f0-9]?([A-Fa-f0-9]?([A-Fa-f0-9])))'我提供

using ${find_string//pattern/replacement_string} where pattern is , , #[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]?([A-Fa-f0-9]?([A-Fa-f0-9]?([A-Fa-f0-9])))' that I supply.

在下面的代码中，当我从文件中读取代码行时，仅打印匹配 pattern 的 line ，即 find_string 我想要输出字符串.

In the code below, simply the line matching pattern is printed i.e find_string, when I read lines of code from a file, whereas I want the output_string to be printed.

pattern="@include circle-progress\(([0-9]{1,3}px, ){2}#[A-Fa-f0-9]
{3,6}\)" /*regex the matches find_string*/

replace_glob=', #[A-Fa-f0-9][A-Fa-f0-9][A-Fa-f0-9]?([A-Fa-f0-9]?([A-
Fa-f0-9]?([A-Fa-f0-9])))' /*glob pattern in the string to be replaced*/

while IFS='' read -r line || [[ -n "$line" ]]; do
   if [[ $line =~ $pattern ]] 
   then
      echo "${line//$replace_glob/}" 
   fi
done < "$1"

推荐答案

参数扩展中的模式不是正则表达式，但遵循与全局模式匹配相同的规则:

The pattern in parameter expansion is not a regular expression but follows the same rules as glob pattern matching:

• * :匹配任何字符序列
• ?:匹配任何字符
• [ .. ] :集合中的任何字符
• [^ .. ] 或 [！ .. ] :任何未设置的字符

• * : matches any character sequence
• ? : matches any character
• [..] : any character in set
• [^..] or [!..] : any character not in set

带有shell选项: shopt -s extglob ，具有更多功能，但少于正则表达式

with shell option : shopt -s extglob, some more features but less than regular expressions

• @( .. | .. ):匹配一次
• ?( .. | .. ):匹配0或1次
• *( .. | .. ):匹配0次或多次
• ！( .. ):与所有匹配，除了

• @(..|..) : match any once
• ?(..|..) : match any 0 or 1 times
• *(..|..) : match any 0 or more times
• !(..) : matches all except

但是bash支持一些基本的正则表达式，以下方法应该起作用:

However bash supports some basic regex, following should work:

string='@include circle-progress(38px, 30px, #4eb630)'
pattern='@include circle-progress\([ ]*[0-9]{1,3}px,[ ]*[0-9]{1,3}px(,[ ]*#[A-Fa-f0-9]{3,6}[ ]*)\)'
[[ $string =~ $pattern ]] && echo "${string//"${BASH_REMATCH[1]}"}"

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