ALIASES(5)

🦋 aliases(5) — the aliases file for sendmail 🦋

okay bestie, welcome to the File Formats Manual entry for aliases(5) — it’s giving old-school mail-router energy, and we are going to get through it together 💖

✨ NAME ✨

aliases — aliases file for sendmail

🌟 SYNOPSIS 🌟

aliases

💖 DESCRIPTION 💖

This file describes user ID aliases used by sendmail. It lives in /etc, no cap, and it’s formatted as a series of lines that look like this:

name: addr_1, addr_2, addr_3, . . .

The name is the name to alias, and the addr_n are the aliases for that name. And addr_n can be another alias, a local username, a local filename, a command, an include file, or an external address. versatile icon behavior ✨

🧁 Local Username 🧁

username

The username must be available via getpwnam(3). like, it has to be lookup-able, periodt.

🍓 Local Filename 🍓

/path/name

Messages are appended to the file specified by the full pathname — and yes, that means it starts with a slash (/). full path main character energy 💅

🎀 Command 🎀

|command

A command starts with a pipe symbol (|), and it receives messages via standard input. pipe it, bestie 🫶

🦋 Include File 🦋

:include: /path/name

The aliases in pathname are added to the aliases for name. it’s literally an alias field trip 🌈

💜 E-Mail Address 💜

user@domain

An e-mail address in RFC 822 format. classic, iconic, no notes ✨

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Lines beginning with white space are continuation lines. Another way to continue lines is by placing a backslash directly before a newline. Lines beginning with # are comments.

Aliasing occurs only on local names. Loops can not occur, since no message will be sent to any person more than once. love that for us — no cursed infinite loop situation 😭

If an alias is found for name, sendmail then checks for an alias for owner-name. If it is found and the result of the lookup expands to a single address, the envelope sender address of the message is rewritten to that address. If it is found and the result expands to more than one address, the envelope sender address is changed to owner-name. okay so that’s the owner-name lore 👑

After aliasing has been done, local and valid recipients who have a .forward file in their home directory have messages forwarded to the list of users defined in that file.

This is only the raw data file; the actual aliasing information is placed into a binary format in the file /etc/aliases.db using the program newaliases(1). A newaliases command should be executed each time the aliases file is changed for the change to take effect. so like… don’t forget to run it, bestie 💀

🎀 SEE ALSO 🎀

• newaliases(1), dbm(3), dbopen(3), db_open(3), sendmail(8)
• SENDMAIL Installation and Operation Guide.
• SENDMAIL An Internetwork Mail Router.

💀 BUGS 💀

If you have compiled sendmail with DBM support instead of NEWDB, you may have encountered problems in dbm(3) restricting a single alias to about 1000 bytes of information. You can get longer aliases by “chaining”; that is, make the last name in the alias be a dummy name which is a continuation alias. not the 1000-byte limit 😭 but chaining is the workaround, iykyk 🫶

🌸 HISTORY 🌸

The aliases file format appeared in 4.0BSD. vintage! iconic! historic! 👑

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that’s the whole page, bestie — footer check: $Date: 2013-11-22 20:51:55 $, and the manual tag is ALIASES(5). byeee 💜💅