<s>
For	O
many	O
command	O
line	O
interpreters	O
(	O
“	O
shell	O
”	O
)	O
of	O
Unix	B-Application
operating	I-Application
systems	I-Application
,	O
the	O
input	B-Operating_System
field	I-Operating_System
separators	I-Operating_System
(	O
IFS	O
)	O
variable	O
is	O
often	O
 [ incorrectly ] 	O
referred	O
to	O
as	O
"	O
internal	O
"	O
field	O
separators	O
.	O
</s>
<s>
From	O
the	O
Bash4	O
man	B-Protocol
page	I-Protocol
:	O
</s>
<s>
The	O
shell	O
treats	O
each	O
character	O
of	O
as	O
a	O
delimiter	B-Algorithm
,	O
and	O
splits	O
the	O
results	O
of	O
the	O
other	O
expansions	O
into	O
words	O
on	O
these	O
characters	O
.	O
</s>
<s>
If	O
is	O
unset	O
,	O
or	O
its	O
value	O
is	O
exactly	O
,	O
the	O
default	O
,	O
then	O
sequences	O
of	O
,	O
,	O
and	O
at	O
the	O
beginning	O
and	O
end	O
of	O
the	O
results	O
of	O
the	O
previous	O
expansions	O
are	O
ignored	O
,	O
and	O
any	O
sequence	O
of	O
characters	O
not	O
at	O
the	O
beginning	O
or	O
end	O
serves	O
to	O
delimit	B-Algorithm
words	O
.	O
</s>
<s>
Any	O
character	O
in	O
that	O
is	O
not	O
whitespace	O
,	O
along	O
with	O
any	O
adjacent	O
whitespace	O
characters	O
,	O
delimits	B-Algorithm
a	O
field	O
.	O
</s>
<s>
A	O
sequence	O
of	O
whitespace	O
characters	O
is	O
also	O
treated	O
as	O
a	O
delimiter	B-Algorithm
.	O
</s>
<s>
According	O
to	O
the	O
Open	O
Group	O
Base	O
Specifications	O
,	O
IFS	O
is	O
an	O
abbreviation	O
for	O
"	O
input	B-Operating_System
field	I-Operating_System
separators	I-Operating_System
"	O
.	O
</s>
<s>
IFS	O
is	O
often	O
 [ incorrectly ] 	O
referred	O
to	O
as	O
"	O
internal	B-Operating_System
field	I-Operating_System
separators	I-Operating_System
"	O
on	O
the	O
internet	O
.	O
</s>
<s>
IFS	O
was	O
usable	O
as	O
an	O
exploit	O
in	O
some	O
versions	O
of	O
Unix	B-Application
.	O
</s>
