<s>
vi	B-Application
(	O
pronounced	O
as	O
distinct	O
letters	O
,	O
)	O
is	O
a	O
screen-oriented	O
text	B-Application
editor	I-Application
originally	O
created	O
for	O
the	O
Unix	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
The	O
portable	O
subset	O
of	O
the	O
behavior	O
of	O
vi	B-Application
and	O
programs	O
based	O
on	O
it	O
,	O
and	O
the	O
ex	B-Device
editor	O
language	O
supported	O
within	O
these	O
programs	O
,	O
is	O
described	O
by	O
(	O
and	O
thus	O
standardized	O
by	O
)	O
the	O
Single	O
Unix	B-Application
Specification	O
and	O
POSIX	O
.	O
</s>
<s>
The	O
original	O
code	O
for	O
vi	B-Application
was	O
written	O
by	O
Bill	O
Joy	O
in	O
1976	O
,	O
as	O
the	O
visual	O
mode	B-General_Concept
for	O
a	O
line	B-Application
editor	I-Application
called	O
ex	B-Device
that	O
Joy	O
had	O
written	O
with	O
Chuck	O
Haley	O
.	O
</s>
<s>
Bill	O
Joy	O
's	O
ex	B-Device
1.1	O
was	O
released	O
as	O
part	O
of	O
the	O
first	O
Berkeley	B-Operating_System
Software	I-Operating_System
Distribution	I-Operating_System
(	O
BSD	B-Operating_System
)	O
Unix	B-Application
release	O
in	O
March	O
1978	O
.	O
</s>
<s>
It	O
was	O
not	O
until	O
version	O
2.0	O
of	O
ex	B-Device
,	O
released	O
as	O
part	O
of	O
Second	O
BSD	B-Operating_System
in	O
May	O
1979	O
that	O
the	O
editor	O
was	O
installed	O
under	O
the	O
name	O
"	O
vi	B-Application
"	O
(	O
which	O
took	O
users	O
straight	O
into	O
ex	B-Device
's	O
visual	O
mode	B-General_Concept
)	O
,	O
and	O
the	O
name	O
by	O
which	O
it	O
is	O
known	O
today	O
.	O
</s>
<s>
Some	O
current	O
implementations	O
of	O
vi	B-Application
can	O
trace	O
their	O
source	O
code	O
ancestry	O
to	O
Bill	O
Joy	O
;	O
others	O
are	O
completely	O
new	O
,	O
largely	O
compatible	O
reimplementations	O
.	O
</s>
<s>
The	O
name	O
"	O
vi	B-Application
"	O
is	O
derived	O
from	O
the	O
shortest	O
unambiguous	O
abbreviation	O
for	O
the	O
ex	B-Device
command	O
visual	O
,	O
which	O
switches	O
the	O
ex	B-Device
line	B-Application
editor	I-Application
to	O
its	O
full-screen	O
mode	B-General_Concept
.	O
</s>
<s>
In	O
addition	O
to	O
various	O
non	O
–	O
free	B-Application
software	I-Application
variants	O
of	O
vi	B-Application
distributed	O
with	O
proprietary	O
implementations	O
of	O
Unix	B-Application
,	O
vi	B-Application
was	O
opensourced	O
with	O
OpenSolaris	B-Operating_System
,	O
and	O
several	O
free	B-Application
and	I-Application
open	I-Application
source	I-Application
software	I-Application
vi	B-Application
clones	O
exist	O
.	O
</s>
<s>
A	O
2009	O
survey	O
of	O
Linux	O
Journal	O
readers	O
found	O
that	O
vi	B-Application
was	O
the	O
most	O
widely	O
used	O
text	B-Application
editor	I-Application
among	O
respondents	O
,	O
beating	O
gedit	B-Language
,	O
the	O
second	O
most	O
widely	O
used	O
editor	O
,	O
by	O
nearly	O
a	O
factor	O
of	O
two	O
(	O
36%	O
to	O
19%	O
)	O
.	O
</s>
<s>
vi	B-Application
was	O
derived	O
from	O
a	O
sequence	O
of	O
UNIX	B-Application
command	I-Application
line	B-Application
editors	I-Application
,	O
starting	O
with	O
ed	B-Application
,	O
which	O
was	O
a	O
line	B-Application
editor	I-Application
designed	O
to	O
work	O
well	O
on	O
teleprinters	O
,	O
rather	O
than	O
display	B-Device
terminals	I-Device
.	O
</s>
<s>
Within	O
AT&T	O
Corporation	O
,	O
where	O
ed	B-Application
originated	O
,	O
people	O
seemed	O
to	O
be	O
happy	O
with	O
an	O
editor	O
as	O
basic	O
and	O
unfriendly	O
as	O
ed	B-Application
,	O
George	O
Coulouris	O
recalls	O
:	O
</s>
<s>
They	O
carried	O
on	O
with	O
TTYs	O
and	O
other	O
printing	O
terminals	O
for	O
a	O
long	O
time	O
,	O
and	O
when	O
they	O
did	O
buy	O
screens	O
for	O
everyone	O
,	O
they	O
got	O
Tektronix	B-General_Concept
4014s	I-General_Concept
.	O
</s>
<s>
Thus	O
it	O
had	O
to	O
fall	O
to	O
someone	O
else	O
to	O
pioneer	O
screen	O
editing	O
for	O
Unix	B-Application
,	O
and	O
that	O
was	O
us	O
initially	O
,	O
and	O
we	O
continued	O
to	O
do	O
so	O
for	O
many	O
years	O
.	O
</s>
<s>
Coulouris	O
considered	O
the	O
cryptic	O
commands	O
of	O
ed	B-Application
to	O
be	O
only	O
suitable	O
for	O
"	O
immortals	O
"	O
,	O
and	O
thus	O
in	O
February	O
1976	O
,	O
he	O
enhanced	O
ed	B-Application
(	O
using	O
Ken	O
Thompson	O
's	O
ed	B-Application
source	O
as	O
a	O
starting	O
point	O
)	O
to	O
make	O
em	O
(	O
the	O
"	O
editor	O
for	O
mortals	O
"	O
)	O
while	O
acting	O
as	O
a	O
lecturer	O
at	O
Queen	O
Mary	O
College	O
.	O
</s>
<s>
The	O
em	O
editor	O
was	O
designed	O
for	O
display	B-Device
terminals	I-Device
and	O
was	O
a	O
single-line-at-a-time	O
visual	O
editor	O
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
first	O
programs	O
on	O
Unix	B-Application
to	O
make	O
heavy	O
use	O
of	O
"	O
raw	O
terminal	O
input	O
mode	B-General_Concept
"	O
,	O
in	O
which	O
the	O
running	O
program	O
,	O
rather	O
than	O
the	O
terminal	O
device	O
driver	O
,	O
handled	O
all	O
keystrokes	O
.	O
</s>
<s>
Inspired	O
by	O
em	O
,	O
and	O
by	O
their	O
own	O
tweaks	O
to	O
ed	B-Application
,	O
Bill	O
Joy	O
and	O
Chuck	O
Haley	O
,	O
both	O
graduate	O
students	O
at	O
UC	O
Berkeley	O
,	O
took	O
code	O
from	O
em	O
to	O
make	O
en	O
,	O
and	O
then	O
"	O
extended	O
"	O
en	O
to	O
create	O
ex	B-Device
version	O
0.1	O
.	O
</s>
<s>
After	O
Haley	O
's	O
departure	O
,	O
Bruce	O
Englar	O
encouraged	O
Joy	O
to	O
redesign	O
the	O
editor	O
,	O
which	O
he	O
did	O
June	O
through	O
October	O
1977	O
adding	O
a	O
full-screen	O
visual	O
mode	B-General_Concept
to	O
exwhich	O
came	O
to	O
be	O
vi	B-Application
.	O
</s>
<s>
vi	B-Application
and	O
ex	B-Device
share	O
their	O
code	O
;	O
vi	B-Application
is	O
the	O
ex	B-Device
binary	B-Application
launching	O
with	O
the	O
capability	O
to	O
render	O
the	O
text	O
being	O
edited	O
onto	O
a	O
computer	O
terminalit	O
is	O
ex	B-Device
's	O
visual	O
mode	B-General_Concept
.	O
</s>
<s>
The	O
name	O
vi	B-Application
comes	O
from	O
the	O
abbreviated	O
ex	B-Device
command	O
(	O
vi	B-Application
)	O
to	O
enter	O
the	O
visual	O
mode	B-General_Concept
from	O
within	O
it	O
.	O
</s>
<s>
The	O
longform	O
command	O
to	O
do	O
the	O
same	O
was	O
visual	O
,	O
and	O
the	O
name	O
vi	B-Application
is	O
explained	O
as	O
a	O
contraction	O
of	O
visual	O
in	O
later	O
literature	O
.	O
</s>
<s>
vi	B-Application
is	O
also	O
the	O
shell	B-Application
command	I-Application
to	O
launch	O
ex/vi	B-Application
in	O
the	O
visual	O
mode	B-General_Concept
directly	O
,	O
from	O
within	O
a	O
shell	B-Operating_System
.	O
</s>
<s>
According	O
to	O
Joy	O
,	O
many	O
of	O
the	O
ideas	O
in	O
this	O
visual	O
mode	B-General_Concept
were	O
taken	O
from	O
Bravothe	O
bimodal	O
text	B-Application
editor	I-Application
developed	O
at	O
Xerox	O
PARC	O
for	O
the	O
Alto	B-Device
.	O
</s>
<s>
In	O
an	O
interview	O
about	O
vi	B-Application
's	O
origins	O
,	O
Joy	O
said	O
:	O
</s>
<s>
A	O
lot	O
of	O
the	O
ideas	O
for	O
the	O
screen	O
editing	O
mode	B-General_Concept
were	O
stolen	O
from	O
a	O
Bravo	B-Protocol
manual	O
I	O
surreptitiously	O
looked	O
at	O
and	O
copied	O
.	O
</s>
<s>
Dot	O
is	O
really	O
the	O
double-escape	O
from	O
Bravo	B-Protocol
,	O
the	O
redo	O
command	O
.	O
</s>
<s>
There	O
were	O
some	O
things	O
stolen	O
from	O
ed	B-Application
—	O
we	O
got	O
a	O
manual	O
page	O
for	O
the	O
Toronto	O
version	O
of	O
ed	B-Application
,	O
which	O
I	O
think	O
Rob	O
Pike	O
had	O
something	O
to	O
do	O
with	O
.	O
</s>
<s>
Joy	O
used	O
a	O
Lear	O
Siegler	O
ADM-3A	B-Device
terminal	O
.	O
</s>
<s>
On	O
this	O
terminal	O
,	O
the	O
Escape	B-Device
key	I-Device
was	O
at	O
the	O
location	O
now	O
occupied	O
by	O
the	O
Tab	O
key	O
on	O
the	O
widely	O
used	O
IBM	B-Device
PC	I-Device
keyboard	I-Device
(	O
on	O
the	O
left	O
side	O
of	O
the	O
alphabetic	O
part	O
of	O
the	O
keyboard	B-Device
,	O
one	O
row	O
above	O
the	O
middle	O
row	O
)	O
.	O
</s>
<s>
This	O
made	O
it	O
a	O
convenient	O
choice	O
for	O
switching	O
vi	B-Application
modes	O
.	O
</s>
<s>
Also	O
,	O
the	O
keys	O
h	O
,	O
j	O
,	O
k	O
,	O
l	O
served	O
double	O
duty	O
as	O
cursor	O
movement	O
keys	O
and	O
were	O
inscribed	O
with	O
arrows	O
,	O
which	O
is	O
why	O
vi	B-Application
uses	O
them	O
in	O
that	O
way	O
.	O
</s>
<s>
The	O
ADM-3A	B-Device
had	O
no	O
other	O
cursor	O
keys	O
.	O
</s>
<s>
Joy	O
was	O
responsible	O
for	O
creating	O
the	O
first	O
BSD	B-Operating_System
Unix	I-Operating_System
release	O
in	O
March	O
,	O
1978	O
,	O
and	O
included	O
ex	B-Device
1.1	O
(	O
dated	O
1	O
February	O
1978	O
)	O
in	O
the	O
distribution	O
,	O
thereby	O
exposing	O
his	O
editor	O
to	O
an	O
audience	O
beyond	O
UC	O
Berkeley	O
.	O
</s>
<s>
From	O
that	O
release	O
of	O
BSD	B-Operating_System
Unix	I-Operating_System
onwards	O
,	O
the	O
only	O
editors	O
that	O
came	O
with	O
the	O
Unix	B-Application
system	I-Application
were	O
ed	B-Application
and	O
ex	B-Device
.	O
</s>
<s>
In	O
a	O
1984	O
interview	O
,	O
Joy	O
attributed	O
much	O
of	O
the	O
success	O
of	O
vi	B-Application
to	O
the	O
fact	O
that	O
it	O
was	O
bundled	O
for	O
free	O
,	O
whereas	O
other	O
editors	O
,	O
such	O
as	O
Emacs	B-Application
,	O
could	O
cost	O
hundreds	O
of	O
dollars	O
.	O
</s>
<s>
Eventually	O
it	O
was	O
observed	O
that	O
most	O
ex	B-Device
users	O
were	O
spending	O
all	O
their	O
time	O
in	O
visual	O
mode	B-General_Concept
,	O
and	O
thus	O
in	O
ex	B-Device
2.0	O
(	O
released	O
as	O
part	O
of	O
Second	O
Berkeley	B-Operating_System
Software	I-Operating_System
Distribution	I-Operating_System
in	O
May	O
,	O
1979	O
)	O
,	O
Joy	O
created	O
vi	B-Application
as	O
a	O
hard	B-Application
link	I-Application
to	O
ex	B-Device
,	O
such	O
that	O
when	O
invoked	O
as	O
vi	B-Application
,	O
ex	B-Device
would	O
automatically	O
start	O
up	O
in	O
its	O
visual	O
mode	B-General_Concept
.	O
</s>
<s>
Thus	O
,	O
vi	B-Application
is	O
not	O
the	O
evolution	O
of	O
ex	B-Device
,	O
vi	B-Application
is	O
ex	B-Device
.	O
</s>
<s>
Joy	O
described	O
ex	B-Device
2.0	O
(	O
vi	B-Application
)	O
as	O
a	O
very	O
large	O
program	O
,	O
barely	O
able	O
to	O
fit	O
in	O
the	O
memory	O
of	O
a	O
PDP-11/70	O
,	O
thus	O
although	O
vi	B-Application
may	O
be	O
regarded	O
as	O
a	O
small	O
,	O
lightweight	O
,	O
program	O
today	O
,	O
it	O
was	O
not	O
seen	O
that	O
way	O
early	O
in	O
its	O
history	O
.	O
</s>
<s>
By	O
version	O
3.1	O
,	O
shipped	O
with	O
3BSD	O
in	O
December	O
1979	O
,	O
the	O
full	O
version	O
of	O
vi	B-Application
was	O
no	O
longer	O
able	O
to	O
fit	O
in	O
the	O
memory	O
of	O
a	O
PDP-11	O
;	O
the	O
editor	O
would	O
be	O
also	O
too	O
big	O
to	O
run	O
on	O
PC/IX	B-Operating_System
for	O
the	O
IBM	B-Device
PC	I-Device
in	O
1984	O
.	O
</s>
<s>
Joy	O
continued	O
to	O
be	O
lead	O
developer	O
for	O
vi	B-Application
until	O
version	O
2.7	O
in	O
June	O
1979	O
,	O
and	O
made	O
occasional	O
contributions	O
to	O
vi	B-Application
's	O
development	O
until	O
at	O
least	O
version	O
3.5	O
in	O
August	O
1980	O
.	O
</s>
<s>
In	O
discussing	O
the	O
origins	O
of	O
vi	B-Application
and	O
why	O
he	O
discontinued	O
development	O
,	O
Joy	O
said	O
:	O
</s>
<s>
I	O
wish	O
we	O
had	O
n't	O
used	O
all	O
the	O
keys	O
on	O
the	O
keyboard	B-Device
.	O
</s>
<s>
I	O
think	O
one	O
of	O
the	O
interesting	O
things	O
is	O
that	O
vi	B-Application
is	O
really	O
a	O
mode-based	O
editor	O
.	O
</s>
<s>
I	O
think	O
as	O
mode-based	O
editors	O
go	O
,	O
it	O
's	O
pretty	O
good	O
.	O
</s>
<s>
One	O
of	O
the	O
good	O
things	O
about	O
EMACS	B-Application
,	O
though	O
,	O
is	O
its	O
programmability	O
and	O
the	O
modelessness	O
.	O
</s>
<s>
I	O
also	O
was	O
n't	O
very	O
good	O
at	O
optimizing	O
code	O
when	O
I	O
wrote	O
vi	B-Application
.	O
</s>
<s>
What	O
actually	O
happened	O
was	O
that	O
I	O
was	O
in	O
the	O
process	O
of	O
adding	O
multiwindows	O
to	O
vi	B-Application
when	O
we	O
installed	O
our	O
VAX	B-Device
,	O
which	O
would	O
have	O
been	O
in	O
December	O
of	O
'	O
78	O
.	O
</s>
<s>
If	O
that	O
scrunch	O
had	O
not	O
happened	O
,	O
vi	B-Application
would	O
have	O
multiple	O
windows	O
,	O
and	O
I	O
might	O
have	O
put	O
in	O
some	O
programmability	O
—	O
but	O
I	O
do	O
n't	O
know	O
.	O
</s>
<s>
The	O
fundamental	O
problem	O
with	O
vi	B-Application
is	O
that	O
it	O
does	O
n't	O
have	O
a	O
mouse	O
and	O
therefore	O
you	O
've	O
got	O
all	O
these	O
commands	O
.	O
</s>
<s>
But	O
fundamentally	O
,	O
vi	B-Application
is	O
still	O
ed	B-Application
inside	O
.	O
</s>
<s>
In	O
1979	O
,	O
Mary	O
Ann	O
Horton	O
took	O
on	O
responsibility	O
for	O
vi	B-Application
.	O
</s>
<s>
Horton	O
added	O
support	O
for	O
arrow	O
and	O
function	B-Application
keys	I-Application
,	O
macros	O
,	O
and	O
improved	O
performance	O
by	O
replacing	O
termcap	B-Application
with	O
terminfo	B-Device
.	O
</s>
<s>
Up	O
to	O
version	O
3.7	O
of	O
vi	B-Application
,	O
created	O
in	O
October	O
1981	O
,	O
UC	O
Berkeley	O
was	O
the	O
development	O
home	O
for	O
vi	B-Application
,	O
but	O
with	O
Bill	O
Joy	O
's	O
departure	O
in	O
early	O
1982	O
to	O
join	O
Sun	O
Microsystems	O
,	O
and	O
T	O
's	O
UNIX	B-Operating_System
System	I-Operating_System
V	I-Operating_System
(	O
January	O
1983	O
)	O
adopting	O
vi	B-Application
,	O
changes	O
to	O
the	O
vi	B-Application
codebase	O
happened	O
more	O
slowly	O
and	O
in	O
a	O
more	O
dispersed	O
and	O
mutually	O
incompatible	O
way	O
.	O
</s>
<s>
Commercial	O
Unix	B-Application
vendors	O
,	O
such	O
as	O
Sun	O
,	O
HP	O
,	O
DEC	O
,	O
and	O
IBM	O
each	O
received	O
copies	O
of	O
the	O
vi	B-Application
source	O
,	O
and	O
their	O
operating	O
systems	O
,	O
Solaris	B-Application
,	O
HP-UX	B-Application
,	O
Tru64	B-Operating_System
UNIX	I-Operating_System
,	O
and	O
AIX	B-Application
,	O
today	O
continue	O
to	O
maintain	O
versions	O
of	O
vi	B-Application
directly	O
descended	O
from	O
the	O
3.7	O
release	O
,	O
but	O
with	O
added	O
features	O
,	O
such	O
as	O
adjustable	O
key	O
mappings	O
,	O
encryption	O
,	O
and	O
wide	O
character	O
support	O
.	O
</s>
<s>
Because	O
Joy	O
had	O
begun	O
with	O
Ken	O
Thompson	O
's	O
ed	B-Application
editor	O
,	O
ex	B-Device
and	O
vi	B-Application
were	O
derivative	O
works	O
and	O
could	O
not	O
be	O
distributed	O
except	O
to	O
people	O
who	O
had	O
an	O
AT&T	O
source	O
license	O
.	O
</s>
<s>
People	O
looking	O
for	O
a	O
free	O
Unix-style	B-Operating_System
editor	O
would	O
have	O
to	O
look	O
elsewhere	O
.	O
</s>
<s>
By	O
1985	O
,	O
a	O
version	O
of	O
Emacs	B-Application
(	O
MicroEMACS	B-Language
)	O
was	O
available	O
for	O
a	O
variety	O
of	O
platforms	O
,	O
but	O
it	O
was	O
not	O
until	O
June	O
1987	O
that	O
STEVIE	B-Language
(	O
ST	B-Device
Editor	O
for	O
VI	B-Application
Enthusiasts	O
)	O
,	O
a	O
limited	O
vi	B-Application
clone	O
,	O
appeared	O
.	O
</s>
<s>
In	O
early	O
January	O
1990	O
,	O
Steve	O
Kirkendall	O
posted	O
a	O
new	O
clone	O
of	O
vi	B-Application
,	O
Elvis	B-Device
,	O
to	O
the	O
Usenet	B-Application
newsgroup	O
comp.os.minix	O
,	O
aiming	O
for	O
a	O
more	O
complete	O
and	O
more	O
faithful	O
clone	O
of	O
vi	B-Application
than	O
STEVIE	B-Language
.	O
</s>
<s>
Andrew	O
Tanenbaum	O
quickly	O
asked	O
the	O
community	O
to	O
decide	O
on	O
one	O
of	O
these	O
two	O
editors	O
to	O
be	O
the	O
vi	B-Application
clone	O
in	O
Minix	B-Operating_System
;	O
Elvis	B-Device
was	O
chosen	O
,	O
and	O
remains	O
the	O
vi	B-Application
clone	O
for	O
Minix	B-Operating_System
today	O
.	O
</s>
<s>
In	O
1989	O
Lynne	O
Jolitz	O
and	O
William	O
Jolitz	O
began	O
porting	O
BSD	B-Operating_System
Unix	I-Operating_System
to	O
run	O
on	O
386	B-General_Concept
class	O
processors	O
,	O
but	O
to	O
create	O
a	O
free	O
distribution	O
they	O
needed	O
to	O
avoid	O
any	O
AT&	O
T-contaminated	O
code	O
,	O
including	O
Joy	O
's	O
vi	B-Application
.	O
</s>
<s>
To	O
fill	O
the	O
void	O
left	O
by	O
removing	O
vi	B-Application
,	O
their	O
1992	O
386BSD	B-Operating_System
distribution	O
adopted	O
Elvis	B-Device
as	O
its	O
vi	B-Application
replacement	O
.	O
</s>
<s>
386BSD	B-Operating_System
's	O
descendants	O
,	O
FreeBSD	B-Operating_System
and	O
NetBSD	B-Device
,	O
followed	O
suit	O
.	O
</s>
<s>
But	O
at	O
UC	O
Berkeley	O
,	O
Keith	O
Bostic	O
wanted	O
a	O
"	O
bug	O
for	O
bug	O
compatible	O
"	O
replacement	O
for	O
Joy	O
's	O
vi	B-Application
for	O
4.4BSD-Lite	O
.	O
</s>
<s>
Using	O
Kirkendall	O
's	O
Elvis	B-Device
(	O
version	O
1.8	O
)	O
as	O
a	O
starting	O
point	O
,	O
Bostic	O
created	O
nvi	B-Device
,	O
releasing	O
it	O
in	O
the	O
northern	O
spring	O
of	O
1994	O
.	O
</s>
<s>
When	O
FreeBSD	B-Operating_System
and	O
NetBSD	B-Device
resynchronized	O
the	O
4.4-Lite2	O
codebase	O
,	O
they	O
too	O
switched	O
over	O
to	O
Bostic	O
's	O
nvi	B-Device
,	O
which	O
they	O
continue	O
to	O
use	O
today	O
.	O
</s>
<s>
Despite	O
the	O
existence	O
of	O
vi	B-Application
clones	O
with	O
enhanced	O
featuresets	O
,	O
sometime	O
before	O
June	O
2000	O
,	O
Gunnar	O
Ritter	O
ported	O
Joy	O
's	O
vi	B-Application
codebase	O
(	O
taken	O
from	O
2.11BSD	O
,	O
February	O
1992	O
)	O
to	O
modern	O
Unix-based	O
operating	O
systems	O
,	O
such	O
as	O
Linux	O
and	O
FreeBSD	B-Operating_System
.	O
</s>
<s>
Ritter	O
continued	O
to	O
make	O
small	O
enhancements	O
to	O
the	O
vi	B-Application
codebase	O
similar	O
to	O
those	O
done	O
by	O
commercial	O
Unix	B-Application
vendors	O
still	O
using	O
Joy	O
's	O
codebase	O
,	O
including	O
changes	O
required	O
by	O
the	O
POSIX.2	O
standard	O
for	O
vi	B-Application
.	O
</s>
<s>
But	O
although	O
Joy	O
's	O
vi	B-Application
was	O
now	O
once	O
again	O
available	O
for	O
BSD	B-Operating_System
Unix	I-Operating_System
,	O
it	O
arrived	O
after	O
the	O
various	O
BSD	B-Operating_System
flavors	O
had	O
committed	O
themselves	O
to	O
nvi	B-Device
,	O
which	O
provides	O
a	O
number	O
of	O
enhancements	O
over	O
traditional	O
vi	B-Application
,	O
and	O
drops	O
some	O
of	O
its	O
legacy	O
features	O
(	O
such	O
as	O
open	O
mode	B-General_Concept
for	O
editing	O
one	O
line	O
at	O
a	O
time	O
)	O
.	O
</s>
<s>
It	O
is	O
in	O
some	O
sense	O
,	O
a	O
strange	O
inversion	O
that	O
BSD	B-Operating_System
Unix	I-Operating_System
,	O
where	O
Joy	O
's	O
vi	B-Application
codebase	O
began	O
,	O
no	O
longer	O
uses	O
it	O
,	O
and	O
the	O
AT&	O
T-derived	O
Unixes	B-Application
,	O
which	O
in	O
the	O
early	O
days	O
lacked	O
Joy	O
's	O
editor	O
,	O
are	O
the	O
ones	O
that	O
now	O
use	O
and	O
maintain	O
modified	O
versions	O
of	O
his	O
code	O
.	O
</s>
<s>
Over	O
the	O
years	O
since	O
its	O
creation	O
,	O
vi	B-Application
became	O
the	O
de	O
facto	O
standard	O
Unix	B-Application
editor	O
and	O
a	O
hacker	O
favorite	O
outside	O
of	O
MIT	O
until	O
the	O
rise	O
of	O
Emacs	B-Application
after	O
about	O
1984	O
.	O
</s>
<s>
The	O
Single	O
UNIX	B-Application
Specification	O
specifies	O
vi	B-Application
,	O
so	O
every	O
conforming	O
system	O
must	O
have	O
it	O
.	O
</s>
<s>
vi	B-Application
is	O
still	O
widely	O
used	O
by	O
users	O
of	O
the	O
Unix	B-Application
family	O
of	O
operating	O
systems	O
.	O
</s>
<s>
About	O
half	O
the	O
respondents	O
in	O
a	O
1991	O
USENET	B-Application
poll	O
preferred	O
vi	B-Application
.	O
</s>
<s>
In	O
1999	O
,	O
Tim	O
O'Reilly	O
,	O
founder	O
of	O
the	O
eponymous	O
computer	O
book	O
publishing	O
company	O
,	O
stated	O
that	O
his	O
company	O
sold	O
more	O
copies	O
of	O
its	O
vi	B-Application
book	O
than	O
its	O
emacs	B-Application
book	O
.	O
</s>
<s>
vi	B-Application
is	O
a	O
modal	O
editor	O
:	O
it	O
operates	O
in	O
either	O
insert	O
mode	B-General_Concept
(	O
where	O
typed	O
text	O
becomes	O
part	O
of	O
the	O
document	O
)	O
or	O
command	O
mode	B-General_Concept
(	O
where	O
keystrokes	O
are	O
interpreted	O
as	O
commands	O
that	O
control	O
the	O
edit	O
session	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
typing	O
while	O
in	O
command	O
mode	B-General_Concept
switches	O
the	O
editor	O
to	O
insert	O
mode	B-General_Concept
,	O
but	O
typing	O
again	O
at	O
this	O
point	O
places	O
an	O
"	O
i	O
"	O
character	O
in	O
the	O
document	O
.	O
</s>
<s>
From	O
insert	O
mode	B-General_Concept
,	O
pressing	O
switches	O
the	O
editor	O
back	O
to	O
command	O
mode	B-General_Concept
.	O
</s>
<s>
A	O
perceived	O
advantage	O
of	O
vi	B-Application
's	O
separation	O
of	O
text	O
entry	O
and	O
command	O
modes	O
is	O
that	O
both	O
text	B-Application
editing	I-Application
and	O
command	O
operations	O
can	O
be	O
performed	O
without	O
requiring	O
the	O
removal	O
of	O
the	O
user	O
's	O
hands	O
from	O
the	O
home	O
row	O
.	O
</s>
<s>
As	O
non-modal	O
editors	O
usually	O
have	O
to	O
reserve	O
all	O
keys	O
with	O
letters	O
and	O
symbols	O
for	O
the	O
printing	O
of	O
characters	O
,	O
any	O
special	O
commands	O
for	O
actions	O
other	O
than	O
adding	O
text	O
to	O
the	O
buffer	O
must	O
be	O
assigned	O
to	O
keys	O
that	O
do	O
not	O
produce	O
characters	O
,	O
such	O
as	O
function	B-Application
keys	I-Application
,	O
or	O
combinations	O
of	O
modifier	B-Device
keys	I-Device
such	O
as	O
,	O
and	O
with	O
regular	O
keys	O
.	O
</s>
<s>
Vi	B-Application
has	O
the	O
property	O
that	O
most	O
ordinary	O
keys	O
are	O
connected	O
to	O
some	O
kind	O
of	O
command	O
for	O
positioning	O
,	O
altering	O
text	O
,	O
searching	O
and	O
so	O
forth	O
,	O
either	O
singly	O
or	O
in	O
key	O
combinations	O
.	O
</s>
<s>
Other	O
types	O
of	O
editors	O
generally	O
require	O
the	O
user	O
to	O
move	O
their	O
hands	O
from	O
the	O
home	O
row	O
when	O
touch	B-Device
typing	I-Device
:	O
</s>
<s>
To	O
use	O
a	O
mouse	O
to	O
select	O
text	O
,	O
commands	O
,	O
or	O
menu	O
items	O
in	O
a	O
GUI	B-Application
editor	O
.	O
</s>
<s>
To	O
the	O
arrow	O
keys	O
or	O
editing	O
functions	O
(	O
Home	O
/	O
End	O
or	O
Function	B-Application
Keys	I-Application
)	O
.	O
</s>
<s>
To	O
invoke	O
commands	O
using	O
modifier	B-Device
keys	I-Device
in	O
conjunction	O
with	O
the	O
standard	O
typewriter	O
keys	O
.	O
</s>
<s>
For	O
instance	O
,	O
in	O
vi	B-Application
,	O
replacing	O
a	O
word	O
is	O
replacement	O
text	O
,	O
which	O
is	O
a	O
combination	O
of	O
two	O
independent	O
commands	O
(	O
change	O
and	O
word-motion	O
)	O
together	O
with	O
a	O
transition	O
into	O
and	O
out	O
of	O
insert	O
mode	B-General_Concept
.	O
</s>
<s>
A	O
human	O
–	O
computer	O
interaction	O
textbook	O
notes	O
on	O
its	O
first	O
page	O
that	O
"	O
One	O
of	O
the	O
classic	O
UI	O
foibles	O
—	O
told	O
and	O
re-told	O
by	O
HCI	O
educators	O
around	O
the	O
world	O
—	O
is	O
the	O
vi	B-Application
editor	I-Application
's	O
lack	O
of	O
feedback	O
when	O
switching	O
between	O
modes	O
.	O
</s>
<s>
Many	O
a	O
user	O
made	O
the	O
mistake	O
of	O
providing	O
input	O
while	O
in	O
command	O
mode	B-General_Concept
or	O
entering	O
a	O
command	O
while	O
in	O
input	O
mode.	O
"	O
</s>
<s>
Vim	B-Application
"	O
Vi	B-Application
IMproved	I-Application
"	O
has	O
many	O
additional	O
features	O
compared	O
to	O
vi	B-Application
,	O
including	O
(	O
scriptable	O
)	O
syntax	O
highlighting	O
,	O
mouse	O
support	O
,	O
graphical	O
versions	O
,	O
visual	O
mode	B-General_Concept
,	O
many	O
new	O
editing	O
commands	O
and	O
a	O
large	O
amount	O
of	O
extension	O
in	O
the	O
area	O
of	O
ex	B-Device
commands	O
.	O
</s>
<s>
Vim	B-Application
is	O
included	O
with	O
almost	O
every	O
Linux	O
distribution	O
(	O
and	O
is	O
also	O
shipped	O
with	O
every	O
copy	O
of	O
Apple	O
macOS	B-Application
)	O
.	O
</s>
<s>
Vim	B-Application
also	O
has	O
a	O
vi	B-Application
compatibility	O
mode	B-General_Concept
,	O
in	O
which	O
Vim	B-Application
is	O
more	O
compatible	O
with	O
vi	B-Application
than	O
it	O
would	O
be	O
otherwise	O
,	O
although	O
some	O
vi	B-Application
features	O
,	O
such	O
as	O
open	O
mode	B-General_Concept
,	O
are	O
missing	O
in	O
Vim	B-Application
,	O
even	O
in	O
compatibility	O
mode	B-General_Concept
.	O
</s>
<s>
This	O
mode	B-General_Concept
is	O
controlled	O
by	O
the	O
option	O
.	O
</s>
<s>
It	O
is	O
automatically	O
turned	O
on	O
by	O
Vim	B-Application
when	O
it	O
is	O
started	O
in	O
a	O
situation	O
that	O
looks	O
as	O
if	O
the	O
software	O
might	O
be	O
expected	O
to	O
be	O
vi	B-Application
compatible	O
.	O
</s>
<s>
Vim	B-Application
features	O
that	O
do	O
not	O
conflict	O
with	O
vi	B-Application
compatibility	O
are	O
always	O
available	O
,	O
regardless	O
of	O
the	O
setting	O
.	O
</s>
<s>
Vim	B-Application
was	O
derived	O
from	O
a	O
port	O
of	O
STEVIE	B-Language
to	O
the	O
Amiga	B-Device
.	O
</s>
<s>
Elvis	B-Device
is	O
a	O
free	O
vi	B-Application
clone	O
for	O
Unix	B-Application
and	O
other	O
operating	O
systems	O
written	O
by	O
Steve	O
Kirkendall	O
.	O
</s>
<s>
Elvis	B-Device
introduced	O
a	O
number	O
of	O
features	O
now	O
present	O
in	O
other	O
vi	B-Application
clones	O
,	O
including	O
allowing	O
the	O
cursor	O
keys	O
to	O
work	O
in	O
input	O
mode	B-General_Concept
.	O
</s>
<s>
Elvis	B-Device
1.x	O
was	O
used	O
as	O
the	O
starting	O
point	O
for	O
nvi	B-Device
,	O
but	O
Elvis	B-Device
2.0	O
added	O
numerous	O
features	O
,	O
including	O
multiple	O
buffers	O
,	O
windows	O
,	O
display	O
modes	O
,	O
and	O
file	O
access	O
schemes	O
.	O
</s>
<s>
Elvis	B-Device
is	O
the	O
standard	O
version	O
of	O
vi	B-Application
shipped	O
on	O
Slackware	B-Application
Linux	I-Application
,	O
Kate	O
OS	O
and	O
MINIX	B-Operating_System
.	O
</s>
<s>
The	O
most	O
recent	O
version	O
of	O
Elvis	B-Device
is	O
2.2	O
,	O
released	O
in	O
October	O
2003	O
.	O
</s>
<s>
nvi	B-Device
is	O
an	O
implementation	O
of	O
the	O
ex/vi	B-Application
text	B-Application
editor	I-Application
originally	O
distributed	O
as	O
part	O
of	O
the	O
final	O
official	O
Berkeley	B-Operating_System
Software	I-Operating_System
Distribution	I-Operating_System
(	O
4.4	O
BSD-Lite	O
)	O
.	O
</s>
<s>
This	O
is	O
the	O
version	O
of	O
vi	B-Application
that	O
is	O
shipped	O
with	O
all	O
BSD-based	O
open	O
source	O
distributions	O
.	O
</s>
<s>
Beyond	O
1.79	O
,	O
from	O
October	O
,	O
1996	O
,	O
which	O
is	O
the	O
recommended	O
stable	O
version	O
,	O
there	O
have	O
been	O
"	O
development	O
releases	O
"	O
of	O
nvi	B-Device
,	O
the	O
most	O
recent	O
of	O
which	O
is	O
1.81.6	O
,	O
from	O
November	O
,	O
2007	O
.	O
</s>
<s>
vile	B-Application
was	O
initially	O
derived	O
from	O
an	O
early	O
version	O
of	O
Microemacs	B-Language
in	O
an	O
attempt	O
to	O
bring	O
the	O
Emacs	B-Application
multi-window/multi	O
-buffer	O
editing	O
paradigm	O
to	O
vi	B-Application
users	O
,	O
and	O
was	O
first	O
published	O
on	O
Usenet	B-Application
's	O
alt.sources	O
in	O
1991	O
.	O
</s>
<s>
BusyBox	B-Application
,	O
a	O
set	O
of	O
standard	O
Linux	O
utilities	O
in	O
a	O
single	O
executable	B-Application
,	O
includes	O
a	O
tiny	O
vi	B-Application
clone	O
.	O
</s>
<s>
Neovim	O
,	O
a	O
refactor	O
of	O
Vim	B-Application
,	O
which	O
it	O
strives	O
to	O
supersede	O
.	O
</s>
