Using SCO Shell Mail

Sending large files via mail

There is a limitation on the size of message you can send over the mail system. If, for example, you want to include a large file (above 32KB) in a message, the recipient may find that part of the file has been lost (truncated) during the transfer, although no error message will appear. You can find out the size of a file by entering:

!l filename

See the discussion on working with files and directories in the Operating System User's Guide or the ls(C) manual page for more information about the l command.

One solution is to compress and encode a file before including it in your message. Compressing a file reduces its size by about 50%; encoding the file increases the size of the compressed file by about 30%, so you end up with a compressed and encoded file that is about two thirds the size of the original. If this still leaves a file that is too large to send, you should, if possible, split the file into smaller files before compressing and encoding them.

The reason why you should encode a compressed file before you send it is because compressed files may include characters that are not recognizable to SCO Shell Mail. Although you may be able to send the compressed file, it may well be truncated or incorrectly transmitted by SCO Shell Mail.

If you are a SCO Shell Mail user, the encoding of a file is done automatically for you when you attach the file to a message. So, if you want to send a compressed file to someone, you should always attach it to the message instead of including it in the message. If, for some reason, you need to include the file in a message, you should follow the procedure given in ``Including information from other applications in a message''.

Because you can only compress a file from the command line (that is, there is no SCO Shell command for doing this), enter the following UNIX system commands from within SCO Shell using an exclamation mark.

Assume that you have a file called myfile that you want to send via mail to one of your colleagues. To compress the file, type:

!compress -c myfile > myfile.Z

The compressed file is named myfile.Z; attach this file to the mail message to be sent, but do not edit its contents.

The recipient of your mail message can recover a copy of the original file by saving the attachment to a file (here named mmsg), and entering the following command:

!uudecode -s mmsg > myfile

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© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003