When I send an ADD command with a really long address, LISTSERV treats the command as two separate lines and it fails. How do I fix this?

This happens because your command has wrapped to a second line. LISTSERV treats each separate physical line of the message as a separate command line. For instance if you send

QUIET ADD MYLIST someone.with.a.real.long.userid.that.wraps@hishost.com His Name

your mail client or mail server will probably wrap that line, and LISTSERV will probably respond

> QUIET ADD MYLIST someone.with.a.real.long.userid.that.wraps@hishost.com

someone.with.a.real.long.userid.that.wraps@HISHOST.COM  is not  yet in  the

signup file. Please specify the full name of that person, as in "ADD MYLIST

JOE@XYZ.EDU Joe H. Smith".

> His Name

Unknown command - "HIS". Try HELP.

In order to send commands that span multiple lines, you have to use special formatting called a "continuation card".

Continuation cards can be used to split any long command into two or more 80-character cards. In that case you must insert a "//<space>" string before the first line of the command text and a space followed by a comma at the end of all but the last line of the command text so that LISTSERV considers the multiple lines to be a control card followed by continuation cards, and performs the required concatenation. For instance,

// QUIET ADD MYLIST someone.with.a.real.long.userid.that.wraps@hishost.com ,

His Name

is read by LISTSERV as one single line and the command will succeed. Note that the spaces are mandatory after the "//" and before the comma; if they are omitted the command will still fail.