$sed 's/This is my \( *\),.*is \(.*\)/\1:\2/g' pets.txt     This is my cat    my cat's name is betty    This is my dog    my dog's name is frank    This is my fish    my fish's name is george    This is my goat    my goat's name is adam不知道我哪里错了,得不到下面的结果cat:bettydog:frankfish:georgegoat:adam