<s>
The	O
MH	B-Protocol
Message	I-Protocol
Handling	I-Protocol
System	I-Protocol
is	O
a	O
free	B-Application
,	O
open	O
source	O
e-mail	B-Protocol
client	I-Protocol
.	O
</s>
<s>
It	O
is	O
different	O
from	O
almost	O
all	O
other	O
mail	O
reading	O
systems	O
in	O
that	O
,	O
instead	O
of	O
a	O
single	O
program	O
,	O
it	O
is	O
made	O
from	O
several	O
different	O
programs	O
which	O
are	O
designed	O
to	O
work	O
from	O
the	O
command	O
line	O
provided	O
by	O
the	O
shell	B-Application
on	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
Taken	O
together	O
,	O
these	O
design	O
choices	O
mean	O
that	O
it	O
is	O
very	O
easy	O
and	O
natural	O
to	O
script	O
actions	O
on	O
mail	O
messages	O
using	O
the	O
normal	O
shell	B-Language
scripting	I-Language
tools	O
.	O
</s>
<s>
Designed	O
with	O
the	B-Operating_System
Unix	I-Operating_System
philosophy	I-Operating_System
in	O
mind	O
,	O
MH	O
is	O
composed	O
of	O
separate	O
programs	O
such	O
as	O
show	O
,	O
to	O
view	O
a	O
message	O
,	O
scan	O
,	O
to	O
see	O
message	O
titles	O
and	O
rmm	O
to	O
remove	O
messages	O
.	O
</s>
<s>
It	O
was	O
forked	O
from	O
version	O
MH	O
6.8.3	O
by	O
Richard	O
Coleman	O
while	O
working	O
at	O
the	O
Georgia	O
Institute	O
of	O
Technology	O
,	O
and	O
released	O
under	O
the	O
BSD	B-Operating_System
License	I-Operating_System
,	O
.	O
</s>
<s>
mmh	O
(	O
"	O
meillo	O
's	O
mail	O
handler	O
"	O
)	O
is	O
a	O
fork	B-Application
of	O
nmh	O
,	O
but	O
their	O
user	O
interface	O
are	O
incompatible	O
.	O
</s>
<s>
The	O
performance	O
of	O
MH	O
is	O
very	O
much	O
dependent	O
on	O
the	O
file	O
system	O
and	O
other	O
features	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
that	O
it	O
runs	O
on	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
mailbox	O
formats	O
such	O
as	O
mbox	B-Application
which	O
use	O
a	O
single	O
file	O
often	O
require	O
insertion	O
or	O
removal	O
of	O
data	O
in	O
the	O
middle	O
of	O
the	O
file	O
when	O
messages	O
are	O
read	O
or	O
altered	O
and	O
this	O
can	O
be	O
a	O
very	O
slow	O
procedure	O
.	O
</s>
<s>
The	O
maildir	O
storage	O
format	O
made	O
popular	O
by	O
qmail	B-Application
and	O
the	O
Courier	B-Protocol
Mail	I-Protocol
Server	I-Protocol
improves	O
upon	O
several	O
features	O
first	O
shown	O
in	O
MH	O
:	O
a	O
separate	O
file	O
per	O
message	O
,	O
a	O
separate	O
directory	O
per	O
mail	O
"	O
folder	O
,	O
"	O
and	O
exploitation	O
of	O
hardlinks	B-Application
and	O
other	O
advanced	O
filesystem	O
features	O
for	O
improved	O
performance	O
in	O
space	O
and	O
time	O
.	O
</s>
<s>
For	O
a	O
graphical	O
interface	O
,	O
the	O
original	O
program	O
was	O
xmh	O
,	O
an	O
X	B-Operating_System
Window	I-Operating_System
System	I-Operating_System
application	O
.	O
</s>
<s>
After	O
development	O
of	O
xmh	O
ceased	O
,	O
a	O
similar	O
tool	O
called	O
exmh	B-Protocol
was	O
developed	O
in	O
Tcl/Tk	B-Application
;	O
and	O
last	O
updated	O
January	O
7	O
,	O
2004	O
.	O
</s>
<s>
Exmh	B-Protocol
is	O
considered	O
feature-complete	O
and	O
there	O
has	O
been	O
little	O
development	O
beyond	O
bug	O
fixes	O
.	O
</s>
<s>
An	O
Emacs	B-Application
interface	O
to	O
MH	O
is	O
also	O
provided	O
by	O
the	O
MH-E	O
project	O
.	O
</s>
<s>
In	O
addition	O
to	O
these	O
dedicated	O
MH	O
clients	O
,	O
support	O
for	O
MH	O
mailboxes	O
is	O
included	O
in	O
several	O
other	O
clients	O
such	O
as	O
Claws	B-Language
Mail	I-Language
,	O
Novell	B-Language
Evolution	I-Language
,	O
Mutt	B-Device
and	O
Sylpheed	B-Language
.	O
</s>
