[Sed] record

Sed Brackets have no special meaning. If you want to retain the wildcard content, you need to escape it.

Echo "1) Host" | SED's/1) ([A-Z])/$1) $1 /'

There are two problems.

1. First of all, it is the problem mentioned above. The above means to match the string 1) (B) without the significance of variable capture, so the $1 next to it is not a variable.

2. Replace the previously captured content with SED and save it directly in a numeric variable, instead of using characters similar to $1 $2. Therefore, Part 1 represents the content in the first parentheses.

But 1 itself represents the number 1, so it needs to be escaped.

Correct syntax:

Echo "1) Host" | SED's/1) \ ([A-Z] \)/\ 1) \ 1 /'