<s>
The	O
Control	B-Operating_System
Language	I-Operating_System
(	O
CL	B-Operating_System
)	O
is	O
a	O
scripting	B-Language
language	I-Language
originally	O
created	O
by	O
IBM	O
for	O
the	O
System/38	B-Device
Control	B-Operating_System
Program	I-Operating_System
Facility	I-Operating_System
and	O
later	O
used	O
in	O
OS/400	B-Application
(	O
now	O
known	O
as	O
IBM	B-Application
i	I-Application
)	O
.	O
</s>
<s>
It	O
bears	O
a	O
resemblance	O
to	O
the	O
IBM	O
Job	B-Application
Control	I-Application
Language	I-Application
and	O
consists	O
of	O
a	O
set	O
of	O
command	O
objects	O
( *	O
CMD	O
)	O
used	O
to	O
invoke	O
traditional	O
programs	O
or	O
get	O
help	O
on	O
what	O
those	O
programs	O
do	O
.	O
</s>
<s>
CL	B-Operating_System
can	O
also	O
be	O
used	O
to	O
create	O
CL	B-Operating_System
programs	O
(	O
congruent	O
to	O
shell	B-Language
scripts	I-Language
)	O
where	O
there	O
are	O
additional	O
commands	O
that	O
provide	O
program-like	O
functionality	O
(	O
IF/ELSE	O
,	O
variable	O
declaration	O
,	O
file	O
input	O
,	O
etc	O
.	O
)	O
</s>
<s>
Although	O
CL	B-Operating_System
is	O
a	O
scripting	B-Language
language	I-Language
for	O
system	O
administration	O
,	O
it	O
is	O
used	O
mainly	O
to	O
create	O
compiled	O
programs	O
.	O
</s>
<s>
The	O
use	O
of	O
interpreted	O
CL	B-Operating_System
scripts	O
through	O
the	O
SBMDBJOB	O
command	O
is	O
in	O
fact	O
extremely	O
limited	O
.	O
</s>
<s>
While	O
thousands	O
of	O
commands	O
were	O
written	O
by	O
IBM	O
developers	O
to	O
perform	O
system	O
level	O
tasks	O
like	O
compiling	O
programs	O
,	O
backing	O
up	O
data	O
,	O
changing	O
system	O
configurations	O
,	O
displaying	O
system	O
object	B-Device
details	O
,	O
or	O
deleting	O
them	O
,	O
commands	O
are	O
not	O
limited	O
to	O
systems	O
level	O
concerns	O
and	O
can	O
be	O
drafted	O
for	O
user	O
applications	O
as	O
well	O
.	O
</s>
<s>
Parameters	O
(	O
command-line	O
arguments	O
)	O
defined	O
in	O
the	O
main	O
procedures	O
of	O
all	O
traditional	O
System/38	B-Device
and	O
AS/400	O
programs	O
are	O
hard	O
coded	O
lists	O
that	O
are	O
made	O
up	O
of	O
parameters	O
that	O
can	O
be	O
numeric	O
,	O
alphanumeric	O
,	O
boolean	O
,	O
etc	O
.	O
</s>
<s>
This	O
is	O
a	O
stark	O
difference	O
from	O
the	O
Unix	B-Application
and	O
DOS	B-Device
worlds	O
where	O
the	O
parameter	O
list	O
in	O
Unix	B-Language
shell	I-Language
scripts	I-Language
and	O
C	B-Language
programs	I-Language
is	O
a	O
set	O
or	O
array	O
of	O
character	O
pointers	O
and	O
more	O
often	O
than	O
not	O
the	O
parameters	O
are	O
not	O
positionally	O
dependent	O
.	O
</s>
<s>
The	O
developer	O
's	O
solution	O
to	O
this	O
problem	O
was	O
the	O
command	O
object	B-Device
( *	O
CMD	O
)	O
.	O
</s>
<s>
The	O
BNF	O
for	O
a	O
much	O
simplified	O
CL	B-Operating_System
command	O
syntax	O
would	O
be	O
defined	O
as	O
follows	O
:	O
</s>
<s>
The	O
items	O
above	O
that	O
end	O
in	O
-name	O
follow	O
object	B-Device
naming	O
conventions	O
which	O
,	O
generally	O
speaking	O
,	O
means	O
the	O
name	O
starts	O
with	O
a	O
letter	O
and	O
can	O
be	O
up	O
to	O
ten	O
characters	O
in	O
length	O
.	O
</s>
<s>
(	O
CL	B-Operating_System
commands	O
are	O
also	O
case-insensitive	O
.	O
)	O
</s>
<s>
A	O
good	O
example	O
of	O
a	O
typical	O
CL	B-Operating_System
command	O
is	O
the	O
Change	O
Program	O
(	O
CHGPGM	O
)	O
command	O
below	O
:	O
</s>
<s>
All	O
CL	B-Operating_System
commands	O
can	O
be	O
prompted	O
directly	O
from	O
the	O
command	O
line	O
or	O
within	O
CL	B-Operating_System
program	O
source	O
by	O
typing	O
the	O
command	O
and	O
pressing	O
the	O
F4	O
function	B-Application
key	I-Application
.	O
</s>
<s>
An	O
OS/400	B-Application
command	O
can	O
also	O
be	O
prompted	O
by	O
typing	O
a	O
?	O
</s>
<s>
Likewise	O
,	O
"	O
Control	B-Operating_System
Language	I-Operating_System
Programming	I-Operating_System
"	O
was	O
abbreviated	O
CLP	O
,	O
and	O
the	O
source	O
type	O
was	O
accordingly	O
CLP	O
.	O
</s>
<s>
The	O
system	O
will	O
then	O
display	O
a	O
list	O
of	O
commands	O
in	O
the	O
job	O
's	O
library	B-Device
list	O
that	O
match	O
the	O
generic	O
names	O
just	O
typed	O
.	O
</s>
<s>
If	O
one	O
wants	O
to	O
select	O
all	O
commands	O
in	O
a	O
library	B-Device
then	O
prompt	O
this	O
command	O
and	O
enter	O
the	O
special	O
value	O
*	O
ALL	O
.	O
</s>
<s>
The	O
following	O
is	O
a	O
sample	O
of	O
CL	B-Operating_System
programming	I-Operating_System
.	O
</s>
