.TH btoa LOCAL 
.SH NAME
btoa, atob, tarmail, untarmail \- encode/decode binary to printable ASCII
.SH SYNOPSIS
.B btoa
< inbinary
> outtext
.PP
.B atob
< intext
> outbinary
.PP
.B tarmail
who subject files ...
.SH DESCRIPTION
.I btoa
is a filter that reads anything from the standard input, and encodes it into
printable ASCII on the standard output.  It also attaches checksum
information used by the reverse filter "atob" to check integrity.  atob gives
NO output (and exits with an error message) if its input is garbage or the
checksums do not check.
.PP
tarmail ralph here-it-is-ralph foo.c a.out
.PP
.I tarmail
is a shell that tar's up all the given files, pipes them through btoa, and
mails them to the given person with the given subject phrase.  "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.  By using tarmail, binary files and
entire directory structures can be easily transmitted between machines.
Naturally, you should understand what tar itself does before you use tarmail.
.PP
Other uses:
.PP
crypt < secrets | btoa | mail ralph
.PP
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:
.PP
atob < xx | crypt
.PP
(crypt requests the key from the terminal,
and the "secrets" come out on the terminal).
.SH FILES
/usr/local/bin:  the programs
.SH AUTHOR
Paul Rutter
.SH FEATURES
It uses a compact base-85 encoding so that
4 bytes are encoded into 5 characters.
.SH BUGS
It uses an obscure base-85 "squoz code" scheme
to encode 4 bytes into 5 characters.