以下を含む各行から一意の文字列を抽出します。

以下は、ファイルのテキストブロックの例です。

Now is the time for all blah:1; to come to the aid
Now is the time for all blah:1; to come to the aid
Now is the time for all blah:1; to come to the aid
Now is the time for all blah:10; to come to the aid
Go to your happy place  blah:100; to come to the aid
Go to your happy place  blah:4321; to come to the aid
Go to your happy place  blah:4321; to come to the aid
Now is the time for all blah:4321; to come to the aid
Now is the time for all blah:9876; to come to the aid
Now is the time for all blah:108636; to come to the aid
Now is the time for all blah:1194996; to come to the aid

Q：「is the」を含む行からすべての一意の番号を抽出する方法は？

'を使ってみましたgrep -o -P -u '(?<=blah:).*(?=;)が、セミコロンが好きではありません。