.\" Copyright 1993-95 by Carl Harris, Jr. Copyright 1996 by Eric S. Raymond .\" All rights reserved. .\" For license terms, see the file COPYING in this directory. .TH popclient LOCAL .SH NAME popclient \- retrieve mail from a mailserver using Post Office Protocol. .SH SYNOPSIS .B popclient [\fI options \fR] \fI [server-host...]\fR .SH DESCRIPTION .I popclient is a Post Office Protocol compliant mail retrieval client which supports both POP2 (as specified in RFC 937) and POP3 (RFC 1725). .PP Typically, .I popclient will be used to download mail in batch from the remote mailserver specified by .I host to a mail folder on the local disk. The retrieved mail can then be manipulated using a local mail reader, such as .I mail or .I elm. .PP To facilitate the use of .I popclient in scripts, pipelines, etc, it returns an appropriate exit code upon termination -- see EXIT CODES below. .PP The behavior of .I popclient is controlled by comand-line options and a control file, .I ~/.poprc the syntax of which we describe below. Command-line options override .I ~/.poprc declarations. .SH OPTIONS Each server name that you specify (following the options on the command line) will be queried. If you don't specify any servers on the command line, each server in your .I ~/.poprc file will be operated on. .TP .B \-2 Use Post Office Protocol version 2 (POP2). See also the .B \--protocol option, below. .TP .B \-3 Use Post Office Protocol version 3 (POP3). See also the .B \--protocol option, below. .TP .B \-a, --all POP3 only. Retrieve both old (previously retrieved) and new messages from the mailserver. .TP .B \-c, --stdout Causes retrieved messages to be written to stdout instead of a mail folder. See OUTPUT OPTIONS below for a complete description. You may not specify both the .B \-c and .B \-o options on the same command line. .TP .B \-F, --flush POP3 only. Delete old (previously retrieved) messages from the mailserver before retrieving new messages. .TP .B \-f pathname, --poprc pathname Specify an alternate name for the .poprc file. .TP .B \-i pathname, --idfile pathname Specify an alternate name for the .popids file. .TP .B \-k, --keep Keep retrieved messages in folder on remote mailserver. Normally, messages are deleted from the folder on the mailserver after they have been retrieved (unless .I popclient was compiled with the KEEP_IS_DEFAULT option). Specifying the .B keep option causes retrieved messages to remain in your folder on the mailserver. .TP .B \-K, --kill Delete retrieved messages from the remote mailserver. If .I popclient is compiled with the KEEP_IS_DEFAULT option, the .B kill option forces retrieved mail to be deleted. .TP .B \-l lines, --limit lines POP3 only. Retrieve no more than the specified number of lines of each message body (plus message headers). The .B keep option is implied by the .B limit option -- i.e. messages downloaded with the .B limit option remain on the remote mailserver. .TP .B \-m mda, --mda mda Specify a mail delivery agent to use. This can be used to pass fetched mail to programs like procmail. If the MDA string contains %s, that escape will be expanded into your username on the client machine. Some possible MDAs are "/usr/formail", "/usr/bin/deliver %s", "/usr/lib/sendmail -oem %s". .TP .B \--protocol proto Specify the protocol to used when communicating with the remote mailserver. .I proto may be one of the following: .RS .IP POP2 Post Office Protocol 2 .IP POP3 Post Office Protocol 3 .IP APOP Use POP3 with MD5 authentication. .IP RPOP Use POP3 with trusted-host-based authentication (like rlogin/rsh). .I popclient must be installed as a setuid root program to use RPOP. .B \--proto. .RE .TP .B \-o folder, --local folder Causes retrieved messages to be appended to file named by the folder argument. When neither .B \-o nor .B \-c is specified, retrieved messages are appended to the system default mail folder. See OUTPUT OPTIONS below for a complete description. .TP .B \-r folder, --remote folder Causes an alternate mail folder on the mailserver to be retrieved. The syntax of the folder name is server dependent, as is the default behavior when no folder is specified. Fortunately, most POP servers have a reasonable default behavior, so use of this option should be limited to fairly specialized applications. POP3 does not provide a folder specification in the protocol. If the .B remote option is used in conjunction with the POP3 protocol, the remote folder specification is ignored. .TP .B \-s, --silent Silent mode. Suppresses all progress/status messages that are normally echoed to stderr during a POP connection. If both the .B silent and .B verbose options are specified, the .B verbose option takes precedence. .TP .B \-u name, --username name Specifies the user idenfication to be used when logging-in to the mailserver. The appropriate user identification is both server and user dependent. The default is your login name on the machine that is running .I popclient. See USER AUTHENTICATION below for a complete description. .TP .B \-v, --verbose Verbose mode. All control messages passed between .I popclient and the mailserver are echoed to stderr. Specifying .B verbose causes normal progress/status messages which would be redundant or meaningless to be modified or omitted. .TP .B \-N, --norewrite Normally, .I popclient edits RFC-822 address headers (To, From, Cc, Bcc, and Reply-To) in fetched mail so that any mail IDs local to the host are expanded to full addresses (@ and the POP host name are appended). This enables replies on the client to get addressed correctly (otherwise your mailer might think they should be addressed to local users on the client machine). This option disables the rewrite. .TP .B \-V, --version Displays the version information for your copy of .I popclient. No POP connection is made. Instead, for each server specified, all option information that would be computed if .I popclient. were connecting to that server is displayed. .TP .PP .SH PROTOCOL SELECTION The selection of the correct Post Office Protocol (POP2 or POP3) depends upon the configuration of the mailserver from which you retrieve your mail. The system adminstrator who installed .I popclient on your system should have chosen an appropriate default protocol for your mailserver. If you get the message 'Connection refused' when using the default protocol, try specifying .B \-2 or .B \-3 to select a different protocol. If the 'Connection refused' message persists regardless of the protocol selected, it is likely that your mailserver is not running a POP compliant mail service. .PP .SH USER AUTHENTICATION User authentication in .I popclient is very much like the authentication mechanism of .I ftp(1). The correct user-id and password depend upon the underlying security system at the mailserver. .PP If the mailserver is a Unix machine on which you have an ordinary user account, your regular login name and password are used with .I popclient. If you use the same login name on both the server and the client machines, you needn't worry about specifying a user-id with the .B \-u option \-\- the default behavior will use your login name on the client machine as the user-id on the server machine. If you use a different login name on the server machine, specify that login name with the .B \-u option. e.g. if your login name is 'jsmith' on a machine named 'mailgrunt', you would start .I popclient as follows: .IP popclient -u jsmith mailgrunt .PP The default behavior of .I popclient is to prompt you for your mailserver password before the POP connection is established. This is the safest way to use .I popclient and ensures that your password will not be compromised. You may also specify your password in your .I ~/.poprc file. This is convenient when using .I popclient with automated scripts. .PP On mailservers that do not provide ordinary user accounts, your user-id and password are usually assigned by the server administrator when you apply for a mailbox on the server. Contact your server administrator if you don't know the correct user-id and password for your mailbox account. .PP .SH OUTPUT OPTIONS The normal behavior of .I popmail is to deliver mail locally via your system's default mail delivery agent or MDA (usually .I /usr/lib/sendmail but your system may use a different MDA -- the .I popclient configuration process should detect this automatically). You can change the MDA the mail is passed to with the -mda or -m option. .PP Using the .B \-o option, you can specify a different mail folder to which the retrieved messages will be appended; .I popclient always writes the retrieved messages using Unix mail folder format so the folder will be parsed correctly by Unix mail programs such as .I elm or .I pine. .PP If you prefer, for example, to have your POP mail from a machine called 'mailgrunt' stored in the .I mbox file in your home directory, you would start .I popclient as follows: .IP popclient \-o $HOME/mbox mailgrunt .PP Note that the folder specified with .B \-o is write-locked while popclient is writing to it, .PP .I popclient can be used in a shell pipeline by using the .B \-c option. In this mode, .I popclient writes the retrieved messages to stdout, instead of a mail folder. This would allow you, for instance, to pass the incoming mail through a filter that discards mail marked as 'Precedence: junk'. Suppose you've written an AWK script called 'dumpjunk.awk' to implement a junk mail filter. The appropriate syntax to retrieve your mail from 'mailgrunt', pass it through the filter, and write it to a folder called 'realmail' in your home directory would be: .nf popclient -c mailgrunt | awk -f dumpjunk.awk >$HOME/realmail .fi .PP The progress/status messages written to stderr when the .B \-s option has not been specified, do not interfere with the message stream, which is written to stdout. You may even use .B \-v and .B \-c together without corrupting the message stream. It is a good idea to use the .B \-k option when using .B \-c to insure that your messages will not be lost if part of the shell pipeline does not function incorrectly. The safest bet would be something like: .nf popclient -k -c mailgrunt | myfilter >$HOME/filtered.mail .fi .PP followed by .nf popclient -c mailgrunt > /dev/null .fi .PP when you're sure the messages were correctly processed by 'myfilter'. .PP .SH DAEMON MODE The .B --daemon or .B -d option runs .I popmail in daemon mode. You must specify a numeric argument which is a polling interval in seconds. .PP In daemon mode, .I popmail puts itself in background and runs forever, querying each specified host and then sleeping for the given polling interval. .PP Simply invoking .IP popmail -d 900 .PP will, therefore, poll the hosts described in your .I ~/.poprc file once every fifteen minutes. .PP Only one daemon process is permitted per user; in daemon mode, .I popclient makes a per-user lockfile to guarantee this. The option .B --quit will kill a running daemon process. .PP The .B -L or .B --logfile option allows you to redirect status messages emitted while in daemon mode into a specified logfile (follow the option with the logfile name). This is primarily useful for debugging configurations. .SH THE POPRC FILE The preferred way to set up popclient (and the only way if you want to specify a password) is to write a .poprc file in your home directory. To protect the security of your passwords, your ~/.poprc may not have more than u+r,u+w permissions; .I popclient will complain and exit otherwise. .PP Comments begin with a '#' and extend through the end of the line. Otherwise the file consists of a series of server entries. Blank lines between server entries are ignored. Keywords and identifiers are case sensitive. When there is a conflict between the command-line arguments and the arguments in this file, the command-line arguments take precedence. .PP Legal keywords are: server protocol (or proto) username (or user) password (or pass) remotefolder (or remote) localfolder (or local) mda keep flush fetchall rewrite nokeep noflush nofetchall norewrite .PP Legal protocol identifiers are pop2 (or POP2) pop3 (or POP3) imap (or IMAP) apop (or APOP) rpop (or RPOP) .PP Basic format is: .nf server SERVERNAME protocol PROTOCOL username NAME password PASSWORD .fi .PP Example: .nf server pop.provider.net protocol pop3 username jsmith password secret1 .fi .PP Or, using some abbreviations: .nf server pop.provider.net proto pop3 user jsmith password secret1 .fi .PP Multiple servers may be listed: .nf server pop.provider.net proto pop3 user jsmith pass secret1 server other.provider.net proto pop2 user John.Smith pass My^Hat .fi .PP Other possibilities (note use of \ to escape newline -- this is all one server definition. .nf server pop.provider.net \e proto pop3 \e user jsmith \e pass secret1 \e localfolder ~/mbox .fi If you need to include whitespace in a parameter string, enclose the string in double quotes. Thus: .nf server mail.provider.net \e proto pop3 \e user jsmith \e pass secret1 \e mda "/bin/mail %s" .fi Finally, you may have an initial server description headed by the keyword `defaults' instead of `server' followed by a name. Such a record is interpreted as defaults for all quries to use. It may be overwritten by individual server descriptions. So, you could write: .nf defaults \e proto pop3 \e user jsmith \e mda "/bin/mail %s" server pop.provider.net \e pass secret1 \e server mail.provider.net \e pass secret2 \e .fi .SH EXIT CODES To facilitate the use of .I popclient in shell scripts and the like, an exit code is returned to give an indication of what occured during a given POP connection. The exit code can be tested by the script and appropriate action taken. .PP A simple example follows. This Bourne shell script executes .I popclient and, if some messages were successfully retrieved from a mailserver retrieved from the command line, it starts the .I mail utility to read those messages. Otherwise, it prints a brief message, and exits. .EX 0 #!/bin/sh if popclient $1 then mail else echo "No mail to read." fi .EE .PP The exit codes returned by .I popclient are as follows: .IP 0 One or more messages were successfully retrieved. .IP 1 There was no mail awaiting retrieval. .IP 2 An error was encountered when attempting to open a socket for the POP connection. If you don't know what a socket is, don't worry about it -- just treat this as an 'unrecoverable error'. .IP 3 The user authentication step failed. This usually means that a bad user-id or password was specified. .IP 4 Some sort of protocol error was detected. POP is not especially forgiving when it comes to unexpected responses, commands, etc -- the protocol invariably calls for terminating the connection under such error conditions. .IP 5 There was a syntax error in the arguments to .I popclient. .IP 6 Some kind of I/O woes occurred when writing to the local folder. .IP 7 There was an error condition reported by the server (POP3 only). .IP 8 Exclusion error. This means .I popclient either found another copy of itself already running, or failed in such a way that it isn't sure whether another copy is running. .IP 9 Something totally undefined occured. This is usually caused by a bug within .I popclient. Do let me know if this happens. .PP When .I popclient queries more than one host, the returned status is that of the last host queried. .SH AUTHOR .I popclient was written by Carl Harris at Virginia Polytechnic Institute and State University (a.k.a. Virginia Tech). Version 3.0 was extensively improved by Eric S. Raymond and is now maintained by esr.. .PP .SH FILES .TP 5 ~/.poprc default configuration file ~/.popids default location of file associating hosts with last message IDs seen (used only with newer RFC1725-compliant servers supporting the UIDL command). .SH BUGS .PP The UIDL support for RFC1725-compliant servers without LAST is not yet very well tested. .PP No IMAP or RPOP support yet. .PP Send comments, bug reports, gripes, and the like to Eric S. Raymond . .SH NOTE The -p (--password) option of previous versions has been removed -- it encouraged people to expose passwords in scripts. Passwords must now be specified either manually or in your .I ~/.poprc file. .SH SEE ALSO mail(1), binmail(1), sendmail(8), popd(8), RFC 937, RFC 1081, RFC 1082, RFC 1225, RFC 1460, RFC 1725.