<s>
In	O
computing	O
,	O
a	O
shebang	B-Operating_System
is	O
the	O
character	O
sequence	O
consisting	O
of	O
the	O
characters	O
number	O
sign	O
and	O
exclamation	O
mark	O
(	O
)	O
at	O
the	O
beginning	O
of	O
a	O
script	B-Language
.	O
</s>
<s>
It	O
is	O
also	O
called	O
sharp-exclamation	O
,	O
sha-bang	B-Operating_System
,	O
hashbang	B-Operating_System
,	O
pound-bang	B-Operating_System
,	O
or	O
hash-pling	O
.	O
</s>
<s>
When	O
a	O
text	O
file	O
with	O
a	O
shebang	B-Operating_System
is	O
used	O
as	O
if	O
it	O
is	O
an	O
executable	O
in	O
a	O
Unix-like	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
,	O
the	O
program	B-Operating_System
loader	I-Operating_System
mechanism	O
parses	O
the	O
rest	O
of	O
the	O
file	O
's	O
initial	O
line	O
as	O
an	O
interpreter	B-Operating_System
directive	I-Operating_System
.	O
</s>
<s>
The	O
loader	B-Operating_System
executes	O
the	O
specified	O
interpreter	B-Application
program	O
,	O
passing	O
to	O
it	O
as	O
an	O
argument	O
the	O
path	B-Application
that	O
was	O
initially	O
used	O
when	O
attempting	O
to	O
run	O
the	O
script	B-Language
,	O
so	O
that	O
the	O
program	O
may	O
use	O
the	O
file	O
as	O
input	O
data	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
a	O
script	B-Language
is	O
named	O
with	O
the	O
path	B-Application
path/to/script	O
,	O
and	O
it	O
starts	O
with	O
the	O
line	O
#	O
!	O
/bin/sh	B-Device
,	O
then	O
the	O
program	B-Operating_System
loader	I-Operating_System
is	O
instructed	O
to	O
run	O
the	O
program	O
/bin/sh	B-Device
,	O
passing	O
path/to/script	O
as	O
the	O
first	O
argument	O
.	O
</s>
<s>
The	O
shebang	B-Operating_System
line	I-Operating_System
is	O
usually	O
ignored	O
by	O
the	O
interpreter	B-Application
,	O
because	O
the	O
"	O
#	O
"	O
character	O
is	O
a	O
comment	O
marker	O
in	O
many	O
scripting	B-Language
languages	I-Language
;	O
some	O
language	O
interpreters	B-Application
that	O
do	O
not	O
use	O
the	O
hash	O
mark	O
to	O
begin	O
comments	O
still	O
may	O
ignore	O
the	O
shebang	B-Operating_System
line	I-Operating_System
in	O
recognition	O
of	O
its	O
purpose	O
.	O
</s>
<s>
The	O
form	O
of	O
a	O
shebang	B-Operating_System
interpreter	B-Operating_System
directive	I-Operating_System
is	O
as	O
follows	O
:	O
</s>
<s>
in	O
which	O
interpreter	B-Application
is	O
a	O
path	B-Application
to	O
an	O
executable	O
program	O
.	O
</s>
<s>
The	O
space	O
between	O
and	O
interpreter	B-Application
is	O
optional	O
.	O
</s>
<s>
In	O
Linux	B-Application
,	O
the	O
file	O
specified	O
by	O
interpreter	B-Application
can	O
be	O
executed	O
if	O
it	O
has	O
the	O
execute	O
rights	O
and	O
is	O
one	O
of	O
the	O
following	O
:	O
</s>
<s>
On	O
Linux	B-Application
and	O
Minix	B-Operating_System
,	O
an	O
interpreter	B-Application
can	O
also	O
be	O
a	O
script	B-Language
.	O
</s>
<s>
A	O
chain	O
of	O
shebangs	B-Operating_System
and	O
wrappers	O
yields	O
a	O
directly	O
executable	O
file	O
that	O
gets	O
the	O
encountered	O
scripts	O
as	O
parameters	O
in	O
reverse	O
order	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
file	O
/bin/A	O
is	O
an	O
executable	O
file	O
in	O
ELF	O
format	O
,	O
file	O
/bin/B	O
contains	O
the	O
shebang	B-Operating_System
,	O
and	O
file	O
/bin/C	O
contains	O
the	O
shebang	B-Operating_System
,	O
then	O
executing	O
file	O
/bin/C	O
resolves	O
to	O
,	O
which	O
finally	O
resolves	O
to	O
.	O
</s>
<s>
In	O
Solaris	B-Application
-	I-Application
and	O
Darwin-derived	O
operating	O
systems	O
(	O
such	O
as	O
macOS	B-Application
)	O
,	O
the	O
file	O
specified	O
by	O
interpreter	B-Application
must	O
be	O
an	O
executable	O
binary	O
and	O
cannot	O
itself	O
be	O
a	O
script	B-Language
.	O
</s>
<s>
Some	O
typical	O
shebang	B-Operating_System
lines	I-Operating_System
:	O
</s>
<s>
#	O
!	O
/bin/false	O
–	O
Do	O
nothing	O
,	O
but	O
return	O
a	O
non-zero	O
exit	B-Operating_System
status	I-Operating_System
,	O
indicating	O
failure	O
.	O
</s>
<s>
Used	O
to	O
prevent	O
stand-alone	O
execution	O
of	O
a	O
script	B-Language
file	O
intended	O
for	O
execution	O
in	O
a	O
specific	O
context	O
,	O
such	O
as	O
by	O
the	O
.	O
</s>
<s>
command	O
from	O
sh/bash	O
,	O
source	O
from	O
csh/tcsh	O
,	O
or	O
as	O
a	O
.profile	O
,	O
.cshrc	O
,	O
or	O
.login	O
file	O
.	O
</s>
<s>
Shebang	B-Operating_System
lines	I-Operating_System
may	O
include	O
specific	O
options	O
that	O
are	O
passed	O
to	O
the	O
interpreter	B-Application
.	O
</s>
<s>
Interpreter	B-Operating_System
directives	I-Operating_System
allow	O
scripts	O
and	O
data	O
files	O
to	O
be	O
used	O
as	O
commands	O
,	O
hiding	O
the	O
details	O
of	O
their	O
implementation	O
from	O
users	O
and	O
other	O
programs	O
,	O
by	O
removing	O
the	O
need	O
to	O
prefix	O
scripts	O
with	O
their	O
interpreter	B-Application
on	O
the	O
command	O
line	O
.	O
</s>
<s>
A	O
Bourne	B-Device
shell	I-Device
script	B-Language
that	O
is	O
identified	O
by	O
the	O
path	B-Application
some/path/to/foo	O
,	O
has	O
the	O
initial	O
line	O
,	O
</s>
<s>
If	O
/bin/sh	B-Device
specifies	O
the	B-Device
Bourne	I-Device
shell	I-Device
,	O
then	O
the	O
end	O
result	O
is	O
that	O
all	O
of	O
the	O
shell	O
commands	O
in	O
the	O
file	O
some/path/to/foo	O
are	O
executed	O
with	O
the	O
positional	O
variables	O
$1	O
and	O
$2	O
having	O
the	O
values	O
bar	O
and	O
baz	O
,	O
respectively	O
.	O
</s>
<s>
Also	O
,	O
because	O
the	O
initial	O
number	O
sign	O
is	O
the	O
character	O
used	O
to	O
introduce	O
comments	O
in	O
the	B-Device
Bourne	I-Device
shell	I-Device
language	O
(	O
and	O
in	O
the	O
languages	O
understood	O
by	O
many	O
other	O
interpreters	B-Application
)	O
,	O
the	O
whole	O
shebang	B-Operating_System
line	I-Operating_System
is	O
ignored	O
by	O
the	O
interpreter	B-Application
.	O
</s>
<s>
However	O
,	O
it	O
is	O
up	O
to	O
the	O
interpreter	B-Application
to	O
ignore	O
the	O
shebang	B-Operating_System
line	I-Operating_System
;	O
thus	O
,	O
a	O
script	B-Language
consisting	O
of	O
the	O
following	O
two	O
lines	O
simply	O
echos	O
both	O
lines	O
to	O
standard	O
output	O
when	O
run	O
:	O
</s>
<s>
When	O
compared	O
to	O
the	O
use	O
of	O
global	O
association	O
lists	O
between	O
file	O
extensions	O
and	O
the	O
interpreting	O
applications	O
,	O
the	O
interpreter	B-Operating_System
directive	I-Operating_System
method	O
allows	O
users	O
to	O
use	O
interpreters	B-Application
not	O
known	O
at	O
a	O
global	O
system	O
level	O
,	O
and	O
without	O
administrator	O
rights	O
.	O
</s>
<s>
It	O
also	O
allows	O
specific	O
selection	O
of	O
interpreter	B-Application
,	O
without	O
overloading	O
the	O
filename	O
extension	O
namespace	O
(	O
where	O
one	O
file	O
extension	O
refers	O
to	O
more	O
than	O
one	O
file	O
type	O
)	O
,	O
and	O
allows	O
the	O
implementation	O
language	O
of	O
a	O
script	B-Language
to	O
be	O
changed	O
without	O
changing	O
its	O
invocation	O
syntax	O
by	O
other	O
programs	O
.	O
</s>
<s>
Invokers	O
of	O
the	O
script	B-Language
need	O
not	O
know	O
what	O
the	O
implementation	O
language	O
is	O
as	O
the	O
script	B-Language
itself	O
is	O
responsible	O
for	O
specifying	O
the	O
interpreter	B-Application
to	O
use	O
.	O
</s>
<s>
Shebangs	B-Operating_System
must	O
specify	O
absolute	B-Application
paths	I-Application
(	O
or	O
paths	O
relative	O
to	O
current	O
working	O
directory	O
)	O
to	O
system	O
executables	O
;	O
this	O
can	O
cause	O
problems	O
on	O
systems	O
that	O
have	O
a	O
non-standard	O
file	O
system	O
layout	O
.	O
</s>
<s>
Even	O
when	O
systems	O
have	O
fairly	O
standard	O
paths	O
,	O
it	O
is	O
quite	O
possible	O
for	O
variants	O
of	O
the	O
same	O
operating	O
system	O
to	O
have	O
different	O
locations	O
for	O
the	O
desired	O
interpreter	B-Application
.	O
</s>
<s>
Python	B-Language
,	O
for	O
example	O
,	O
might	O
be	O
in	O
/usr/bin/python3	O
,	O
/usr/local/bin/python3	O
,	O
or	O
even	O
something	O
like	O
/home/username/bin/python3	O
if	O
installed	O
by	O
an	O
ordinary	O
user	O
.	O
</s>
<s>
A	O
similar	O
problem	O
exists	O
for	O
the	O
POSIX	O
shell	O
,	O
since	O
POSIX	O
only	O
required	O
its	O
name	O
to	O
be	O
sh	O
,	O
but	O
did	O
not	O
mandate	O
a	O
path	B-Application
.	O
</s>
<s>
A	O
common	O
value	O
is	O
,	O
but	O
some	O
systems	O
such	O
as	O
Solaris	B-Application
have	O
the	O
POSIX-compatible	O
shell	O
at	O
/usr/xpg4/bin/sh	O
.	O
</s>
<s>
In	O
many	O
Linux	B-Application
systems	O
,	O
/bin/sh	B-Device
is	O
a	O
hard	O
or	O
symbolic	B-Application
link	I-Application
to	O
/bin/bash	B-Operating_System
,	O
the	O
Bourne	B-Operating_System
Again	I-Operating_System
shell	I-Operating_System
(	O
BASH	B-Operating_System
)	O
.	O
</s>
<s>
Using	O
bash-specific	O
syntax	O
while	O
maintaining	O
a	O
shebang	B-Operating_System
pointing	O
to	O
sh	O
is	O
also	O
not	O
portable	O
.	O
</s>
<s>
Because	O
of	O
this	O
it	O
is	O
sometimes	O
required	O
to	O
edit	O
the	O
shebang	B-Operating_System
line	I-Operating_System
after	O
copying	O
a	O
script	B-Language
from	O
one	O
computer	O
to	O
another	O
because	O
the	O
path	B-Application
that	O
was	O
coded	O
into	O
the	O
script	B-Language
may	O
not	O
apply	O
on	O
a	O
new	O
machine	O
,	O
depending	O
on	O
the	O
consistency	O
in	O
past	O
convention	O
of	O
placement	O
of	O
the	O
interpreter	B-Application
.	O
</s>
<s>
For	O
this	O
reason	O
and	O
because	O
POSIX	O
does	O
not	O
standardize	O
path	B-Application
names	I-Application
,	O
POSIX	O
does	O
not	O
standardize	O
the	O
feature	O
.	O
</s>
<s>
The	O
GNU	B-Application
Autoconf	I-Application
tool	O
can	O
test	O
for	O
system	O
support	O
with	O
the	O
macro	O
AC_SYS_INTERPRETER	O
.	O
</s>
<s>
is	O
followed	O
by	O
,	O
followed	O
by	O
the	O
desired	O
command	O
without	O
full	B-Application
path	I-Application
,	O
as	O
in	O
this	O
example	O
:	O
</s>
<s>
This	O
mostly	O
works	O
because	O
the	O
path	B-Application
is	O
commonly	O
used	O
for	O
the	O
utility	O
,	O
</s>
<s>
and	O
it	O
invokes	O
the	O
first	O
found	O
in	O
the	O
user	O
's	O
$PATH	B-Application
,	O
typically	O
.	O
</s>
<s>
This	O
still	O
has	O
some	O
portability	O
issues	O
with	O
OpenServer	B-Operating_System
5.0.6	O
and	O
Unicos	B-Operating_System
9.0.2	O
which	O
have	O
only	O
and	O
no	O
.	O
</s>
<s>
Some	O
systems	O
,	O
including	O
Linux	B-Application
,	O
do	O
not	O
split	O
up	O
the	O
arguments	O
;	O
for	O
example	O
,	O
when	O
running	O
the	O
script	B-Language
with	O
the	O
first	O
line	O
like	O
,	O
</s>
<s>
Cygwin	B-Language
also	O
behaves	O
this	O
way	O
.	O
</s>
<s>
Complex	O
interpreter	B-Application
invocations	O
are	O
possible	O
through	O
the	O
use	O
of	O
an	O
additional	O
wrapper	O
.	O
</s>
<s>
FreeBSD	O
6.0	O
(	O
2005	O
)	O
introduced	O
a	O
option	O
to	O
its	O
as	O
it	O
changed	O
the	O
shebang-reading	O
behavior	O
to	O
non-splitting	O
.	O
</s>
<s>
The	O
GNU	B-Operating_System
utility	O
since	O
coreutils	B-Application
8.30	O
(	O
2018	O
)	O
also	O
includes	O
this	O
feature	O
.	O
</s>
<s>
Another	O
problem	O
is	O
scripts	O
containing	O
a	O
carriage	O
return	O
character	O
immediately	O
after	O
the	O
shebang	B-Operating_System
line	I-Operating_System
,	O
perhaps	O
as	O
a	O
result	O
of	O
being	O
edited	O
on	O
a	O
system	O
that	O
uses	O
DOS	O
line	O
breaks	O
,	O
such	O
as	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Some	O
systems	O
interpret	O
the	O
carriage	O
return	O
character	O
as	O
part	O
of	O
the	O
interpreter	B-Application
command	O
,	O
resulting	O
in	O
an	O
error	O
message	O
.	O
</s>
<s>
The	O
shebang	B-Operating_System
is	O
actually	O
a	O
human-readable	O
instance	O
of	O
a	O
magic	O
number	O
in	O
the	O
executable	O
file	O
,	O
the	O
magic	O
byte	O
string	O
being	O
,	O
the	O
two-character	O
encoding	O
in	O
ASCII	B-Protocol
of	O
.	O
</s>
<s>
This	O
magic	O
number	O
is	O
detected	O
by	O
the	O
"	O
exec	B-Operating_System
"	O
family	O
of	O
functions	O
,	O
which	O
determine	O
whether	O
a	O
file	O
is	O
a	O
script	B-Language
or	O
an	O
executable	O
binary	O
.	O
</s>
<s>
The	O
presence	O
of	O
the	O
shebang	B-Operating_System
will	O
result	O
in	O
the	O
execution	O
of	O
the	O
specified	O
executable	O
,	O
usually	O
an	O
interpreter	B-Application
for	O
the	O
script	B-Language
's	O
language	O
.	O
</s>
<s>
It	O
has	O
been	O
claimed	O
that	O
some	O
old	O
versions	O
of	O
Unix	O
expect	O
the	O
normal	O
shebang	B-Operating_System
to	O
be	O
followed	O
by	O
a	O
space	O
and	O
a	O
slash	O
(	O
)	O
,	O
but	O
this	O
appears	O
to	O
be	O
untrue	O
;	O
rather	O
,	O
blanks	O
after	O
the	O
shebang	B-Operating_System
have	O
traditionally	O
been	O
allowed	O
,	O
and	O
sometimes	O
documented	O
with	O
a	O
space	O
(	O
see	O
the	O
1980	O
email	O
in	O
history	O
section	O
below	O
)	O
.	O
</s>
<s>
The	O
shebang	B-Operating_System
characters	O
are	O
represented	O
by	O
the	O
same	O
two	O
bytes	O
in	O
extended	B-Protocol
ASCII	I-Protocol
encodings	O
,	O
including	O
UTF-8	O
,	O
which	O
is	O
commonly	O
used	O
for	O
scripts	O
and	O
other	O
text	O
files	O
on	O
current	O
Unix-like	B-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
However	O
,	O
UTF-8	O
files	O
may	O
begin	O
with	O
the	O
optional	O
byte	O
order	O
mark	O
(	O
BOM	O
)	O
;	O
if	O
the	O
"	O
exec	B-Operating_System
"	O
function	O
specifically	O
detects	O
the	O
bytes	O
and	O
,	O
then	O
the	O
presence	O
of	O
the	O
BOM	O
(	O
)	O
before	O
the	O
shebang	B-Operating_System
will	O
prevent	O
the	O
script	B-Language
interpreter	B-Application
from	O
being	O
executed	O
.	O
</s>
<s>
Some	O
authorities	O
recommend	O
against	O
using	O
the	O
byte	O
order	O
mark	O
in	O
POSIX	O
(	O
Unix-like	B-Operating_System
)	O
scripts	O
,	O
for	O
this	O
reason	O
and	O
for	O
wider	O
interoperability	O
and	O
philosophical	O
concerns	O
.	O
</s>
<s>
Additionally	O
,	O
a	O
byte	O
order	O
mark	O
is	O
not	O
necessary	O
in	O
UTF-8	O
,	O
as	O
that	O
encoding	O
does	O
not	O
have	O
endianness	O
issues	O
;	O
it	O
serves	O
only	O
to	O
identify	O
the	O
encoding	O
as	O
UTF-8	O
.	O
</s>
<s>
An	O
executable	O
file	O
starting	O
with	O
an	O
interpreter	B-Operating_System
directive	I-Operating_System
is	O
simply	O
called	O
a	O
script	B-Language
,	O
often	O
prefaced	O
with	O
the	O
name	O
or	O
general	O
classification	O
of	O
the	O
intended	O
interpreter	B-Application
.	O
</s>
<s>
The	O
name	O
shebang	B-Operating_System
for	O
the	O
distinctive	O
two	O
characters	O
may	O
have	O
come	O
from	O
an	O
inexact	O
contraction	O
of	O
SHArp	O
bang	O
or	O
haSH	B-Operating_System
bang	I-Operating_System
,	O
referring	O
to	O
the	O
two	O
typical	O
Unix	O
names	O
for	O
them	O
.	O
</s>
<s>
Another	O
theory	O
on	O
the	O
sh	O
in	O
shebang	B-Operating_System
is	O
that	O
it	O
is	O
from	O
the	O
default	O
shell	O
sh	O
,	O
usually	O
invoked	O
with	O
shebang	B-Operating_System
.	O
</s>
<s>
The	O
shebang	B-Operating_System
was	O
introduced	O
by	O
Dennis	O
Ritchie	O
between	O
Edition	B-Operating_System
7	I-Operating_System
and	O
8	B-Operating_System
at	O
Bell	O
Laboratories	O
.	O
</s>
<s>
It	O
was	O
also	O
added	O
to	O
the	O
BSD	B-Operating_System
releases	O
from	O
Berkeley	O
's	O
Computer	O
Science	O
Research	O
(	O
present	O
at	O
2.8BSD	O
and	O
activated	O
by	O
default	O
by	O
4.2BSD	O
)	O
.	O
</s>
<s>
As	O
AT&T	O
Bell	O
Laboratories	O
Edition	O
8	B-Operating_System
Unix	O
,	O
and	O
later	O
editions	O
,	O
were	O
not	O
released	O
to	O
the	O
public	O
,	O
the	O
first	O
widely	O
known	O
appearance	O
of	O
this	O
feature	O
was	O
on	O
BSD	B-Operating_System
.	O
</s>
<s>
The	O
lack	O
of	O
an	O
interpreter	B-Operating_System
directive	I-Operating_System
,	O
but	O
support	O
for	O
shell	O
scripts	O
,	O
is	O
apparent	O
in	O
the	O
documentation	O
from	O
Version	B-Operating_System
7	I-Operating_System
Unix	I-Operating_System
in	O
1979	O
,	O
which	O
describes	O
instead	O
a	O
facility	O
of	O
the	B-Device
Bourne	I-Device
shell	I-Device
where	O
files	O
with	O
execute	O
permission	O
would	O
be	O
handled	O
specially	O
by	O
the	O
shell	O
,	O
which	O
would	O
(	O
sometimes	O
depending	O
on	O
initial	O
characters	O
in	O
the	O
script	B-Language
,	O
such	O
as	O
"	O
:	O
"	O
or	O
"	O
#	O
"	O
)	O
spawn	O
a	O
subshell	O
which	O
would	O
interpret	O
and	O
run	O
the	O
commands	O
contained	O
in	O
the	O
file	O
.	O
</s>
<s>
In	O
this	O
model	O
,	O
scripts	O
would	O
only	O
behave	O
as	O
other	O
commands	O
if	O
called	O
from	O
within	O
a	O
Bourne	B-Device
shell	I-Device
.	O
</s>
<s>
An	O
attempt	O
to	O
directly	O
execute	O
such	O
a	O
file	O
via	O
the	O
operating	O
system	O
's	O
own	O
exec( )	O
system	O
trap	O
would	O
fail	O
,	O
preventing	O
scripts	O
from	O
behaving	O
uniformly	O
as	O
normal	O
system	O
commands	O
.	O
</s>
<s>
In	O
later	O
versions	O
of	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
this	O
inconsistency	O
was	O
removed	O
.	O
</s>
<s>
Dennis	O
Ritchie	O
introduced	O
kernel	O
support	O
for	O
interpreter	B-Operating_System
directives	I-Operating_System
in	O
January	O
1980	O
,	O
for	O
Version	B-Operating_System
8	I-Operating_System
Unix	I-Operating_System
,	O
with	O
the	O
following	O
description	O
:	O
</s>
<s>
to	O
be	O
the	O
name	O
of	O
an	O
interpreter	B-Application
for	O
the	O
executed	O
file	O
.	O
</s>
<s>
because	O
they	O
can	O
be	O
the	O
subject	O
of	O
'	O
exec.	O
'	O
</s>
<s>
5	O
)	O
It	O
will	O
allow	O
other	O
interpreters	B-Application
to	O
fit	O
in	O
more	O
smoothly	O
.	O
</s>
<s>
are	O
OK	O
.	O
Use	O
a	O
complete	O
pathname	B-Application
(	O
no	O
search	O
is	O
done	O
)	O
.	O
</s>
<s>
Kernel	O
support	O
for	O
interpreter	B-Operating_System
directives	I-Operating_System
spread	O
to	O
other	O
versions	O
of	O
Unix	O
,	O
and	O
one	O
modern	O
implementation	O
can	O
be	O
seen	O
in	O
the	O
Linux	B-Application
kernel	O
source	O
in	O
fs/binfmt_script.c.	O
</s>
<s>
This	O
mechanism	O
allows	O
scripts	O
to	O
be	O
used	O
in	O
virtually	O
any	O
context	O
normal	O
compiled	O
programs	O
can	O
be	O
,	O
including	O
as	O
full	O
system	O
programs	O
,	O
and	O
even	O
as	O
interpreters	B-Application
of	O
other	O
scripts	O
.	O
</s>
<s>
As	O
a	O
caveat	O
,	O
though	O
,	O
some	O
early	O
versions	O
of	O
kernel	O
support	O
limited	O
the	O
length	O
of	O
the	O
interpreter	B-Operating_System
directive	I-Operating_System
to	O
roughly	O
32	O
characters	O
(	O
just	O
16	O
in	O
its	O
first	O
implementation	O
)	O
,	O
would	O
fail	O
to	O
split	O
the	O
interpreter	B-Application
name	O
from	O
any	O
parameters	O
in	O
the	O
directive	O
,	O
or	O
had	O
other	O
quirks	O
.	O
</s>
<s>
magic	O
number	O
,	O
some	O
scripts	O
lacking	O
interpreter	B-Operating_System
directives	I-Operating_System
(	O
although	O
usually	O
still	O
requiring	O
execute	O
permission	O
)	O
are	O
still	O
runnable	O
by	O
virtue	O
of	O
the	O
legacy	O
script	B-Language
handling	O
of	O
the	B-Device
Bourne	I-Device
shell	I-Device
,	O
still	O
present	O
in	O
many	O
of	O
its	O
modern	O
descendants	O
.	O
</s>
