<s>
An	O
interpreter	B-Operating_System
directive	I-Operating_System
is	O
a	O
computer	B-Language
language	I-Language
construct	O
,	O
that	O
on	O
some	O
systems	O
is	O
better	O
described	O
as	O
an	O
aspect	O
of	O
the	O
system	O
's	O
executable	O
file	O
format	O
,	O
that	O
is	O
used	O
to	O
control	O
which	O
interpreter	B-Application
parses	O
and	O
interprets	O
the	O
instructions	O
in	O
a	O
computer	B-Application
program	I-Application
.	O
</s>
<s>
In	O
Unix	B-Application
,	O
Linux	B-Application
and	O
other	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
the	O
first	O
two	O
bytes	O
in	O
a	O
file	O
can	O
be	O
the	O
characters	O
"	O
#	O
!	O
</s>
<s>
often	O
referred	O
to	O
as	O
shebang	B-Operating_System
,	O
prefix	O
the	O
first	O
line	O
in	O
a	O
script	B-Language
,	O
with	O
the	O
remainder	O
of	O
the	O
line	O
being	O
a	O
command	O
usually	O
limited	O
to	O
a	O
max	O
of	O
14	O
(	O
when	O
introduced	O
)	O
up	O
to	O
usually	O
about	O
80	O
characters	O
in	O
2016	O
.	O
</s>
<s>
If	O
the	O
file	O
system	O
permissions	O
on	O
the	O
script	B-Language
(	O
a	O
file	O
)	O
include	O
an	O
execute	B-General_Concept
permission	O
bit	O
for	O
the	O
user	O
invoking	O
it	O
by	O
its	O
filename	O
(	O
often	O
found	O
through	O
the	O
command	O
search	O
path	O
)	O
,	O
it	O
is	O
used	O
to	O
tell	O
the	O
operating	B-General_Concept
system	I-General_Concept
what	O
interpreter	B-Application
(	O
usually	O
a	O
program	O
that	O
implements	O
a	O
scripting	B-Language
language	I-Language
)	O
to	O
use	O
to	O
execute	B-General_Concept
the	O
script	B-Language
's	O
contents	O
,	O
which	O
may	O
be	O
batch	B-General_Concept
commands	I-General_Concept
or	O
might	O
be	O
intended	O
for	O
interactive	O
use	O
.	O
</s>
<s>
An	O
example	O
would	O
be	O
#	O
!	O
/bin/bash	B-Operating_System
,	O
meaning	O
run	O
this	O
script	B-Language
with	O
the	O
bash	B-Operating_System
shell	I-Operating_System
found	O
in	O
the	O
/bin	O
directory	O
.	O
</s>
<s>
Other	O
systems	O
or	O
files	O
may	O
use	O
some	O
other	O
magic	O
number	O
as	O
the	O
interpreter	B-Operating_System
directives	I-Operating_System
.	O
</s>
