uuencode & uudecode commands can be used to encode a binary file and decode its binary representation.

syntax: uuencode [filename] [decode_path]

filename is the file to be encoded. It takes input from stdin if no source file is provided.

decode_path specifies the path in which decoded contents of the encoded fiel are to be placed.

uudecode decodes the encoded file.

syntax: uudecode -p encoded_file

-p option specifies the decoded contents to be displayed onto stdout.

uuencode can be used along with mailx command to send a file as an attachment.

Eg: uuencode samplefile | mailx -s subject xyz@pqr.com
text_of_message
ctrl-d

Pretty Kool.
If someone asks me how to send a file as an attachment from unix mail,this is the way!

use the below

uuencode

As Saritha mentioned

uuencode can be used along with mailx command to send a file as an attachment !
Great command ! isn't it?