<s>
tail	O
is	O
a	O
program	B-Application
available	O
on	O
Unix	B-Application
,	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
FreeDOS	B-Application
and	O
MSX-DOS	B-Operating_System
used	O
to	O
display	O
the	O
tail	O
end	O
of	O
a	O
text	O
file	B-Operating_System
or	O
piped	O
data	O
.	O
</s>
<s>
The	O
version	O
of	O
tail	O
bundled	O
in	O
GNU	B-Application
coreutils	I-Application
was	O
written	O
by	O
Paul	O
Rubin	O
,	O
David	O
MacKenzie	O
,	O
Ian	O
Lance	O
Taylor	O
,	O
and	O
Jim	O
Meyering	O
.	O
</s>
<s>
The	O
command	B-Application
is	O
available	O
as	O
a	O
separate	O
package	O
for	O
Microsoft	B-Application
Windows	I-Application
as	O
part	O
of	O
the	O
UnxUtils	B-Application
collection	O
of	O
native	B-Language
Win32	B-Library
ports	O
of	O
common	O
GNU	B-Operating_System
Unix-like	B-Operating_System
utilities	O
.	O
</s>
<s>
The	O
FreeDOS	B-Application
version	O
was	O
developed	O
by	O
M	O
.	O
Aitchison	O
.	O
</s>
<s>
A	O
tail	O
command	B-Application
is	O
also	O
part	O
of	O
ASCII	O
's	O
MSX-DOS2	O
Tools	O
for	O
MSX-DOS	B-Operating_System
version	O
2	O
.	O
</s>
<s>
It	O
is	O
a	O
colorized	O
tail	O
programmed	O
in	O
Python	B-Language
which	O
tails	O
and	O
colorizes	O
syslog	O
output	O
.	O
</s>
<s>
Inotail	O
is	O
a	O
deprecated	O
implementation	O
of	O
inotify	B-Application
kernel	B-Operating_System
interface	O
.	O
</s>
<s>
The	O
early	O
implementation	O
of	O
tail	O
polled	O
every	O
second	O
to	O
see	O
if	O
new	O
data	O
can	O
be	O
displayed	O
,	O
as	O
tail	O
implemented	O
inotifiy	O
kernel	B-Operating_System
interface	O
Inotail	O
become	O
deprecated	O
and	O
it	O
is	O
not	O
longer	O
maintained	O
.	O
</s>
<s>
Inotail	O
used	O
the	O
Linux	B-Application
kernel	B-Operating_System
's	O
inotify-interface	O
introduced	O
in	O
version	O
2.6.13	O
in	O
August	O
2005	O
so	O
that	O
it	O
only	O
checks	O
for	O
new	O
data	O
when	O
there	O
really	O
is	O
some	O
.	O
</s>
<s>
It	O
is	O
more	O
or	O
less	O
a	O
combination	O
of	O
tail	O
,	O
sed	B-Application
,	O
watch	O
,	O
CCZE/pctail	O
,	O
grep	B-Application
,	O
diff	B-Application
,	O
Beeper	O
and	O
others	O
.	O
</s>
<s>
The	O
command-syntax	O
is	O
:	O
</s>
<s>
With	O
command	B-Application
line	I-Application
options	I-Application
,	O
the	O
amount	O
of	O
output	O
and	O
the	O
units	O
(	O
lines	O
,	O
blocks	O
or	O
bytes	O
)	O
may	O
be	O
changed	O
.	O
</s>
<s>
Using	O
an	O
older	O
syntax	B-Application
(	O
still	O
used	O
in	O
older	O
version	O
of	O
Sun	O
Solaris	O
as	O
the	O
-n	O
option	O
is	O
not	O
supported	O
)	O
,	O
the	O
last	O
20	O
lines	O
and	O
the	O
last	O
50	O
bytes	O
of	O
filename	O
can	O
be	O
shown	O
with	O
the	O
following	O
command	B-Application
:	O
</s>
<s>
However	O
this	O
syntax	B-Application
is	O
now	O
obsolete	O
and	O
does	O
not	O
conform	O
with	O
the	O
POSIX	O
1003.1-2001	O
standard	O
.	O
</s>
<s>
As	O
with	O
all	O
Unix	B-Application
commands	I-Application
,	O
use	O
man	B-Protocol
pages	I-Protocol
on	O
the	O
running	O
system	O
for	O
specific	O
options	O
and	O
actions	O
.	O
</s>
<s>
has	O
two	O
special	O
command	B-Application
line	I-Application
option	O
and	O
(	O
follow	O
)	O
that	O
allows	O
a	O
file	B-Operating_System
to	O
be	O
monitored	O
.	O
</s>
<s>
Instead	O
of	O
just	O
displaying	O
the	O
last	O
few	O
lines	O
and	O
exiting	O
,	O
displays	O
the	O
lines	O
and	O
then	O
monitors	O
the	O
file	B-Operating_System
.	O
</s>
<s>
As	O
new	O
lines	O
are	O
added	O
to	O
the	O
file	B-Operating_System
by	O
another	O
process	B-Operating_System
,	O
updates	O
the	O
display	O
.	O
</s>
<s>
Ancient	O
versions	O
of	O
tail	O
poll	O
the	O
file	B-Operating_System
every	O
second	O
by	O
default	O
but	O
tail	O
from	O
the	O
GNU	B-Application
coreutils	I-Application
as	O
of	O
version	O
7.5	O
support	O
the	O
inotify	B-Application
infrastructure	O
introduced	O
in	O
Linux	B-Application
kernel	B-Operating_System
version	O
2.6.13	O
in	O
August	O
2005	O
which	O
only	O
check	O
the	O
file	B-Operating_System
when	O
is	O
notified	O
of	O
changes	O
by	O
the	O
kernel	B-Operating_System
.	O
</s>
<s>
The	O
following	O
command	B-Application
will	O
display	O
the	O
last	O
10	O
lines	O
of	O
messages	O
and	O
append	O
new	O
lines	O
to	O
the	O
display	O
as	O
new	O
lines	O
are	O
added	O
to	O
messages	O
:	O
</s>
<s>
To	O
keep	O
following	O
the	O
log	O
even	O
when	O
it	O
is	O
recreated	O
,	O
renamed	O
,	O
or	O
removed	O
as	O
part	O
of	O
log	B-Application
rotation	I-Application
,	O
at	O
least	O
BSD	O
and	O
GNU	B-Operating_System
implementations	O
provide	O
a	O
option	O
which	O
is	O
useful	O
in	O
cases	O
when	O
the	O
user	O
is	O
following	O
a	O
log	O
file	B-Operating_System
that	O
rotates	B-Application
.	O
</s>
<s>
To	O
interrupt	O
while	O
it	O
is	O
monitoring	O
,	O
break-in	O
with	O
Ctrl+C	O
.	O
</s>
<s>
This	O
command	B-Application
can	O
be	O
run	O
"	O
in	O
the	O
background	O
"	O
with	O
,	O
see	O
job	B-Operating_System
control	I-Operating_System
.	O
</s>
<s>
If	O
the	O
user	O
has	O
a	O
command	B-Application
's	O
result	O
to	O
monitor	O
,	O
the	O
watch	O
command	B-Application
can	O
be	O
used	O
.	O
</s>
<s>
There	O
is	O
a	O
GNU	B-Application
Emacs	I-Application
mode	O
that	O
emulates	O
the	O
functionality	O
of	O
,	O
called	O
.	O
</s>
