正则表达式方闭括号

Question

我可以用猛砸，如果我想要一个右方括号]被包括在该组来匹配一组字符

$ [[ a =~ [abc] ]]; echo $? 
0 

然而，它未能

$ [[ a =~ [abc\]] ]]; echo $? 
1 

$ [[ a =~ [abc\\]] ]]; echo $? 
1 

Answer 1

从手册页regex(7)：

To include a literal ']' in the list, make it the first character (fol- 
lowing a possible '^'). 

测试：

$ [[ "]" =~ []abc] ]]; echo $? 
0