mailx is a Unix utility program for sending and receiving mail, also known as a Mail User Agent program. Being a console application with a command syntax similar to ed, it is the POSIX standardized variant^[1] of the Berkeley Mail utility.^[2]

• mail (Unix)

• mailx – Shell and Utilities Reference, The Single UNIX Specification, Version 4 from The Open Group
• History of mail and mailx from the Heirloom Project
• mailx Tutorial from the engineering Dpt. at Purdue University
• mail at GNU Mailutils manual
• S-nail mailx(1) manual