1 Cone©
2CONE(1) Cone: COnsole Newsreader And E CONE(1)
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8 cone - Read and send E-mail messages
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11 cone [-r] [-c directory]
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14 Cone is a console newsreader and E-mail. It is an interactive program
15 for reading and sending E-mail messages. Cone is designed to be
16 intuitive and easy to learn. Starting Cone for the first time displays
17 two links: one for the default system mailbox, and a second link to a
18 quick online tutorial. The online tutorial provides a brief overview of
19 using Cone for reading and sending E-mail.
20 Pressing Q on most screens exits Cone. Cone tries to gracefully log
22 out and shut down all server connections. If Cone cannot log out of a
23 remote server because the remote server is down, press CTRL-C (after Q
24 to terminate Cone).
25 Use CTRL-Z to temporarily suspend Cone and drop back to the shell
27 prompt. Cone remains suspended in the background, and may be restarted
28 by using the shell's fg command.
29 Note
31 Connections to remote mail servers may be disconnected for
32 inactivity if Cone remains suspended for a prolonged period of
33 time. When suspended, Cone cannot maintain any active connections
34 to remote mail servers.
35 The -c option names a directory where Cone saves its configuration
37 files, and defaults to $HOME/.cone. The configuration directory will be
38 created, if necessary.
39 The -r option recovers a backup copy of Cone's configuration file. This
41 option is primarily used when remote configuration is enabled, but the
42 folder that contains Cone's configuration on a remote server was
43 deleted, or is not available. In all cases, Cone makes a daily local
44 configuration file backup. The -r option searches for local
45 configuration file backups, and offers an option to restore the backup
46 copy.
47 Reading local mail with Cone
49 Cone reads local mail from either maildirs (the preferred format) or
50 mailbox files (or "mboxes"). When mboxes are used, Cone does not read
51 the system mailbox file directly (usually /var/spool/something). All
52 messages in the system mailbox are automatically moved to $HOME/Inbox,
53 which is then accessed as if it was the system mailbox. Starting Cone
54 for the first time on an mbox-based system automatically copies all
55 existing mail from the system mailbox file to $HOME/Inbox.
56 This is an intentional design choice. Normal user application cannot
58 create new files in /var/spool; all they can do is read the mailbox
59 file from /var/spool. Therefore, the only way to update the mailbox
60 file is by rewriting it from scratch (more or less). While the mailbox
61 file is in the process of being rewritten, if the Cone process is
62 interrupted, or killed, the resulted in a corrupted system mailbox.
63 There are way to minimize this vulnerability, but it cannot be
64 eliminated completely. Some Linux kernels use an “OOM killer” that may
65 terminate any process when the system memory is low. There is no way to
66 completely prevent corrupted system mailbox files on those kernels.
67 Cone uses an alternative way of updating mboxes. Cone updates mboxes
69 by creating a new mbox file separately, then replacing the original
70 mbox file with the new version. Unfortunately this cannot be done with
71 the system mailbox file, because of the restricted access rights on the
72 system spool directory. To solve this problem Cone automatically copies
73 the system mailbox file to $HOME/Inbox, each time the system mailbox
74 file is opened and whenever new mail is available.
75 Viewing MIME attachments
77 Cone displays text and simple HTML content by itself. Other kinds of
78 attachments may be viewed by using a helper script. Cone invokes a
79 helper script to open a MIME attachment. The helper script's name is
80 “TYPE.SUBTYPE.filter”, where “TYPE” and “SUBTYPE” corresponds to the
81 MIME type and subtype, accordingly. Cone looks for helper scripts in
82 $HOME/.cone (or the directory specified by -c) and in /usr/share/cone.
83 For example, a helper script named “IMAGE.GIF.filter”, if installed, is
85 invoked to process image/gif MIME attachments.
86 Helper scripts
88 Cone runs each helper script twice:
89 TYPE.SUBTYPE.filter check type/subtype
91 When the first argument is “check”, the helper script should
93 terminate with a zero exit code if it is willing to process an
94 attachment whose MIME type is specified by the second argument. A
95 script or a program that's has multiple “TYPE.SUBTYPE.filter” links
96 may use the second argument to identify the attachment's mime type.
97 If the helper script is unable to process the attachment, at this
98 time, it should terminate with a non-zero exit code.
99 The default helper script for image attachments terminates with a
101 non-zero exit code if the DISPLAY environment variable is not
102 initialized. When invoked from an X-Windows terminal, image
103 attachments will be automatically displayed; and image attachments
104 are ignored otherwise on non-graphical consoles.
105 TYPE.SUBTYPE.filter filter type/subtype filename
107 If the helper script initially terminates with a zero exit code, it
109 will be invoked again after the MIME attachment is downloaded and
110 decoded. The first argument will be “filter”, and the attachment's
111 filename is specified by the third argument.
112 Note
114 This is a temporary file, whose extension will not necessary be
115 the file extension associated with this MIME type.
116 The helper script should read and process the file specified by the
118 third argument. Cone interprets anything the helper script writes
119 to standard output as HTML.
120 Note
122 Cone waits until the helper script terminates before displaying
123 the rest of the message. Most helper scripts should run in the
124 background. However, note that Cone removes the temporary file
125 when the original message is closed; the temporary file may be
126 removed any time after the helper script terminates. The helper
127 script should make its own private copy of the file, if
128 necessary.
129 Activating URLs
131 Cone has limited ability to activate URLs in HTML messages. Cone
132 handles “mailto:”URLs by itself. For other URLs Cone runs
133 /usr/share/cone/method.handler with the URL passed as an argument.
134 Cone installs http.handler (hard linked to https.handler). This script
136 checks if firefox or mozilla binaries are found in the current PATH,
137 and runs them.
138 Note
140 Cone also looks method.handler in $HOME/.cone (or the directory
141 specified by -c) in addition to /usr/share/cone.
142
144 $HOME/.cone
145 Configuration files, and other application data. May be modified by
146 the -c option.
147 /usr/share/cone/IMAGE.GIF.filter, /usr/share/cone/IMAGE.JPEG.filter,
149 /usr/share/cone/IMAGE.PNG.filter,
150 /usr/share/cone/APPLICATION.PDF.filter
151 Default helper scripts distributed with Cone.
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154 mailtool(1), sendmail(8).
155
157 Sam Varshavchik
158Cone© 08/25/2016 CONE(1)