Related:

• file signature n. A magic number, sense 3.
• file signature: n. A {magic number}, sense 3. -- The AI Hackers Dictionary
• He must have made a macro of my signature.
• ig block: /sig blok/ [UNIX; often written `.sig' there] n.
  Short for `signature', used specifically to refer to the electronic signature block that most UNIX mail- and news-posting software will {automagically} append to outgoing mail and news....
• ig block /sig blok/ n. [Unix; often written `.sig' there] Short for `signature'
  used specifically to refer to the electronic signature block that most Unix mail- and news-posting software will automagically append to outgoing mail and news....
• A signature short of a book.
• As this is not a real signature, the opinions above may not even be mine. -- DISCLAIMER
• It was pleasant to me to get a letter from you the other day.
  Perhaps I should have found it pleasanter if I had been able to decipher it....