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UUENVIEW(1) General Commands Manual UUENVIEW(1)


uuenview - a powerful encoder for binary files


uuenview [options] file(s)


uuenview encodes a binary file into ASCII text for sending over non-8-bit electronic data channels, such as electronic mail or the usenet. uuenview is a superset of and fully backwards compatible with the standard uuencode(1) command, featuring more comfort and more flexibility.

Files encoded with uuenview are compatible with virtually all decoders, as long as the encoding method (see below) is supported by the remote side. If the remote side uses uudeview(1), there shouldn't be any problems at all.

If properly configured, uuenview can directly send encoded files by email or to the usenet. These messages are wrapped into a proper MIME envelope, which is handy if the recipient uses MIME-compliant mail or news software.



Chooses the Base64 encoding method as specified by the MIME standard.
Chooses the uuencoding method, for compatibility with uuencode(1).
Chooses the yEncoding method.
Chooses the now obsolete xxencoding method.
Sends the file(s) as plain text.
Encodes the file(s) using quoted printable encoding.

These options are positional and affect the encoding of all remaining files on the command line until changed.

When sending, posting or attaching files, the default is to use Base64, resulting in MIME compliant messages. Otherwise, when encoding to standard output or into a file, the default is to use uuencoding.


Specifies that output shall be written into files. These files will have the same base name as the source file and an extension of .001, .002 etc, depending on the number of parts required by the -lines option. The encoded files are written to the current directory.
Same as '-o', but the encoded files are written to the given directory instead.
Mails the encoded file(s), each one probably split into multiple parts, to the given email address. Multiple recipients can be given as a quoted, comma-separated list. On Unix systems, mail is usually piped to sendmail(8).
Posts the encoded file(s), each one probably split into multiple parts, to the given newsgroup. Multiple newsgroups can be given as a quoted, comma-separated list. The inews(1) program is invoked for posting. You may have to set the NNTPSERVER environment variable to your news server.
Attaches files. This feature is expected to be used from shell scripts and the like. In attach mode, a message is read from standard input, complete with headers. The files given on the command line are then "attached" to the message, which is converted, if necessary, to a proper MIME multipart format. The -a option can be combined with -m or -p in order to directly mail or post the result. Else, the message, complete with attachments, is written to standard output.

Uudeview is using a heuristic to determine where the provided message headers end and the message body starts. If the first line does not start with either From or some non-whitespace characters followed by a colon (e.g. "X-header-blah:" or "Patch#1:") uuenview interprets the whole input as message body. Else anything before the first empty line is interpreted as headers and the rest of the provided input is taken as message body.

If no target option is given, the encoded data is printed to standard output.


When mailing or posting a file, it is possible to set certain headers. Be careful to quote parameters that consist of more than one word.

Set the Subject: header line. The file name and part number are automatically appended. Without this, a default subject header is generated.
Set the From: header line.
Set the Reply-To: header line.


Verbosely prints everything the program's trying to do.
Substituting lines with a number, sets the maximum number of encoded lines per part. The encoded data is automatically split into as many parts as required. Line counts less than 200 are ignored. The uuencoding and xxencoding methods encode 45k, and Base64 encodes 57k of data in 1000 lines. If this option is not specified, the default is unlimited lines per part, resulting in exactly one part.
One or more filenames to be processed. To encode a file from the standard input, use a single hyphen '-' and give a filename to be used for the encoded file as the next parameter.

Options may also be set in the $UUENVIEW environment variable, which is read before processing the options on the command line.


Files read from standard input can only be used once, meaning that at most one target option may be given.

Output written to standard output cannot be split into multiple parts. In this case, the -lines option is ignored.

uuenview must be correctly configured at compile time in order for mailing and posting to work. If it doesn't, consult your system administrator. The program used for posting a file can be set at runtime using the INEWS environment variable. This setting overrides the compile-time configuration.

Base64 is not MIME. Base64 is the encoding specified by the MIME standard, but in order for a message to become a proper MIME message, a number of headers are required. uuenview produces these headers when mailing or posting, but not when writing to a file. In this case, uuenview does not have any control over the headers. If you include Base64 output into your messages, they are not MIME-compliant!

If you rename, copy or link the program to uuencode, it may act as a smart replacement for the standard, accepting the same command-line syntax. This has not been well-tested yet.


Encodes the file uudeview.tgz and mails it to both your local system administrator and to your friend Fred at the Somewhere company.

If you give more than one filename on the command line, each file is usually handled separately. A workaround is to send them all as attachment to a single (or empty) mail:

Creates an empty mail and attaches the two given files, encoded in Base64 format, and mails the result to your system administrator.


uudeview(1), uuencode(1), uudecode(1), sendmail(8), inews(1).

The uudeview homepage on the Web,


The program does not detect error conditions when mailing or posting.

Attaching only works reliably if certain headers of the input message (for example Content-Type) are not folded and shorter than 1024 characters.

It is not possible to encode into BinHex.

The program will quite likely fail to handle binary data as input for plain text or quoted-printable attachments. On plain text attachments, the line length (must be less than 998 characters according to MIME) is not enforced.

It is not possible to set the "charset" value of plain text attachments.

It is not possible to set the content type value of attachments.

sendmail(8) stops reading upon a line consisting only of a single dot. uudeview does not check plain text input files against this condition. (The problem is worked around when using quoted-printable, and does not exist with the other encodings.)

June 2001