btoa(1)                                                   btoa(1)



NAME
     btoa, atob, tarmail, untarmail - encode/decode binary to
     printable ASCII

SYNOPSIS
     btoa
     atob
     tarmail [ -u ] who subject files ...
     untarmail [ file ]

DESCRIPTION
     btoa is a filter that reads anything from the standard
     input, and encodes it into printable ASCII on the standard
     output.  It also attaches a header and checksum information
     used by the reverse filter atob to find the start of the
     data and to check integrity.

     Atob reads an encoded file, strips off any leading and
     trailing lines added by mailers, and recreates a copy of the
     the standard output.  Atob gives NO output and exits with an
     error message if its input is garbage or the checksums do
     not check.

     Tarmail is a shell script that tar's up all the given files,
     pipes them through compress, btoa, and mails them to the
     given person with the given subject phrase.

     For example:

             tarmail ralph "here it is ralph" foo.c a.out

     will package up files foo.c and a.out and mail them to ralph
     using subject here it is ralph.  Notice the quotes on the
     subject.  They are necessary to make it one argument to the
     shell.

     The -u option to tarmail is specific to CX/UX and will cause
     tar to archive the given file name arguments utilizing a
     format recognized by versions of tar distributed by the
     University of California at Berkeley (UCB).  UCB tar histor-
     ically appends a slash (/) by default to the end of all
     directory names archived.  The / is used by UCB tar to
     determine whether a directory is being extracted from the
     archive.  The CX/UX version of tar used in tarmail complies
     with the POSIX 1003.1 and X/Open extended tar format which
     does not permit the UCB tar default action.  As a result,
     CX/UX tarmail archives sent to pre-CX/UX 5.3 and non-CX/UX
     systems which utilize the UCB tar will not be readable when
     untarmail or tar is used on them.  Utilizing this option
     will cause CX/UX tar to perform the UCB default action.





Page 1                              CX/UX User's Reference Manual

btoa(1)                                                   btoa(1)



     Tarmail with no args will print a short message reminding
     you what the required args are.  When the mail is received
     at the other end, that person should use mail to save the
     message in some temporary file name (say xx).  Then saying
     untarmail xx will decode the message and untar it.  Untar-
     mail can also be used as a filter.  By using tarmail, binary
     files and entire directory structures can be easily
     transmitted between machines.  Naturally, you should under-
     stand what tar itself does before you use tarmail.

     Other uses:

             compress < secrets | crypt | btoa | mail ralph

     will mail the encrypted contents of the file secrets to
     ralph.  If ralph knows the encryption key, he can decode it
     by saving the mail (say in xx), and then running:

             atob < xx | crypt | uncompress

     (crypt requests the key from the terminal, and the secrets
     come out on the terminal).

AUTHOR
     Paul Rutter (modified by Joe Orost)

FEATURES
     btoa uses a compact base-85 encoding so that 4 bytes are
     encoded into 5 characters (file is expanded by 25%).  As a
     special case, 32-bit zero is encoded as one character.  This
     encoding produces less output than uuencode(1C).

SEE ALSO
     compress(1), crypt(1), uuencode(1C), mail(1)





















Page 2                              CX/UX User's Reference Manual