Editing Email attachment (section)

==History, and technical detail==
Originally, ARPANET, UUCP, and Internet [[SMTP]] email allowed [[ASCII|7-bit ASCII]] text only.  Text files were emailed by including them in the message body.  In the mid 1980s text files could be grouped with [[UNIX]] tools such as bundle<ref>The UNIX Programming Environment, Kernighan and Pike, 1984, p.97</ref><ref>{{cite journal|title=Unix tricks and traps|journal=AUUGN|date=August 1994|volume=15|issue=4|page=87|url=https://books.google.com/books?id=fNSEwqH75t0C&q=shar}}</ref> and [[Shar (file format)|shar]] (shell archive)<ref>Modern versions of [[Shar (file format)|shar]] can deal with binaries, via uuencoding them, but this was not initially the case.</ref> and included in email message bodies, allowing them to be unpacked on remote UNIX systems with a single shell command.

The COMSYS/MSGDMS system at MIT offered "Enclosures" beginning by 1976.<ref>[http://mercury.lcs.mit.edu/~jnc/tech/header/mins02.txt "Jack Haverty, email to Header-People, 8 November 1976"]</ref><ref>[https://www.computerhistory.org/collections/catalog/102806104 "Feinler, Vittal: Email Innovation Timeline, 1 July 2022"]</ref> Users inside COMSYS could receive the enclosure file directly. Messages sent to users out of the COMSYS world sent the enclosure as part of the message body, which was useful only for text files.

Attaching non-text files was first accomplished in 1980 by manually encoding 8-bit files using [[Mary Ann Horton]]'s [[uuencode]], and later using [[BinHex]] or [[xxencode]]<ref>[http://kb.winzip.com/kb/?View=entry&EntryID=103 ''"How do I use UUencode/BinHex/MIME support?"'', winzip.com].</ref> and pasting the resulting text into the body of the message.  When the "Attachment" user interface first appeared on PCs in [[cc:Mail]] around 1985,<ref>{{cite book|author=InfoWorld Media Group, Inc.|title=InfoWorld|url=https://books.google.com/books?id=8C4EAAAAMBAJ&pg=PA41|date=June 3, 1985|publisher=InfoWorld Media Group, Inc.|page=41}}</ref> it used the [[uuencode]] format for SMTP transmission, as did [[Microsoft Mail]] later.

Modern email systems use the [[MIME]] standard, making email attachments more utilitarian and seamless. This was developed by [[Nathaniel Borenstein]] and collaborator [[Ned Freed]]<ref name=kingsley>[https://www.theguardian.com/technology/2012/mar/26/ather-of-the-email-attachment Father of the email attachment], Patrick Kingsley, ''The Guardian'', 26 March 2012</ref><ref>[http://www.networkworld.com/news/2011/020111-mime-internet-email.html?page=1 "The MIME guys: How two Internet gurus changed e-mail forever "] {{Webarchive|url=https://web.archive.org/web/20120125015429/http://www.networkworld.com/news/2011/020111-mime-internet-email.html?page=1 |date=2012-01-25 }}, February 01, 2011, Jon Brodkin, Network World</ref> - with the standard being officially released as [http://tools.ietf.org/html/rfc2045 RFC2045] in 1996.

With MIME, a message and all its attachments are encapsulated in a single [[multipart message]], with [[base64]] encoding used to convert binary into 7-bit ASCII text - or on some modern mail servers, optionally [[8-bit clean|full 8-bit support]] via the [[8BITMIME]] extension.