<s>
In	O
software	O
,	O
a	O
wildcard	B-Algorithm
character	I-Algorithm
is	O
a	O
kind	O
of	O
placeholder	O
represented	O
by	O
a	O
single	O
character	O
,	O
such	O
as	O
an	O
asterisk	B-Language
(	O
)	O
,	O
which	O
can	O
be	O
interpreted	O
as	O
a	O
number	O
of	O
literal	O
characters	O
or	O
an	O
empty	O
string	O
.	O
</s>
<s>
In	O
telecommunications	O
,	O
a	O
wildcard	B-Algorithm
is	O
a	O
character	O
that	O
may	O
be	O
substituted	O
for	O
any	O
of	O
a	O
defined	O
subset	O
of	O
all	O
possible	O
characters	O
.	O
</s>
<s>
In	O
high-frequency	B-Algorithm
(	O
HF	O
)	O
radio	O
automatic	B-Device
link	I-Device
establishment	I-Device
,	O
the	O
wildcard	B-Algorithm
character	I-Algorithm
may	O
be	O
substituted	O
for	O
any	O
one	O
of	O
the	O
36	O
upper-case	O
alphanumeric	O
characters	O
.	O
</s>
<s>
Whether	O
the	O
wildcard	B-Algorithm
character	I-Algorithm
represents	O
a	O
single	O
character	O
or	O
a	O
string	O
of	O
characters	O
must	O
be	O
specified	O
.	O
</s>
<s>
In	O
computer	O
(	O
software	O
)	O
technology	O
,	O
a	O
wildcard	B-Algorithm
is	O
a	O
symbol	O
used	O
to	O
replace	O
or	O
represent	O
one	O
or	O
more	O
characters	O
.	O
</s>
<s>
Algorithms	O
for	O
matching	O
wildcards	B-Algorithm
have	O
been	O
developed	O
in	O
a	O
number	O
of	O
recursive	O
and	O
non-recursive	O
varieties	O
.	O
</s>
<s>
When	O
specifying	O
file	O
names	O
(	O
or	O
paths	O
)	O
in	O
CP/M	B-Application
,	O
DOS	B-Device
,	O
Microsoft	B-Application
Windows	I-Application
,	O
and	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
the	O
asterisk	B-Language
character	O
(	O
,	O
also	O
called	O
"	O
star	O
"	O
)	O
matches	O
zero	O
or	O
more	O
characters	O
.	O
</s>
<s>
If	O
files	O
are	O
named	O
with	O
a	O
date	O
stamp	O
,	O
wildcards	B-Algorithm
can	O
be	O
used	O
to	O
match	O
date	O
ranges	O
,	O
such	O
as	O
*	O
.mp4	O
to	O
select	O
video	O
recordings	O
from	O
,	O
to	O
facilitate	O
file	O
operations	O
such	O
as	O
copying	O
and	O
moving	O
.	O
</s>
<s>
In	O
Unix-like	B-Operating_System
and	O
DOS	B-Device
operating	B-General_Concept
systems	I-General_Concept
,	O
the	O
question	O
mark	O
matches	O
exactly	O
one	O
character	O
.	O
</s>
<s>
In	O
DOS	B-Device
,	O
if	O
the	O
question	O
mark	O
is	O
placed	O
at	O
the	O
end	O
of	O
the	O
word	O
,	O
it	O
will	O
also	O
match	O
missing	O
(	O
zero	O
)	O
trailing	O
characters	O
;	O
for	O
example	O
,	O
the	O
pattern	O
will	O
match	O
and	O
,	O
but	O
not	O
.	O
</s>
<s>
In	O
Unix	B-Application
shells	I-Application
and	O
Windows	B-Application
PowerShell	I-Application
,	O
ranges	O
of	O
characters	O
enclosed	O
in	O
square	O
brackets	O
(	O
and	O
)	O
match	O
a	O
single	O
character	O
within	O
the	O
set	O
;	O
for	O
example	O
,	O
matches	O
any	O
single	O
uppercase	O
or	O
lowercase	O
letter	O
.	O
</s>
<s>
In	O
Unix	B-Application
shells	I-Application
,	O
a	O
leading	O
exclamation	O
mark	O
negates	O
the	O
set	O
and	O
matches	O
only	O
a	O
character	O
not	O
within	O
the	O
list	O
.	O
</s>
<s>
The	O
operation	O
of	O
matching	O
of	O
wildcard	B-Algorithm
patterns	O
to	O
multiple	O
file	O
or	O
path	O
names	O
is	O
referred	O
to	O
as	O
globbing	B-Language
.	O
</s>
<s>
In	O
SQL	B-Language
,	O
wildcard	B-Algorithm
characters	I-Algorithm
can	O
be	O
used	O
in	O
LIKE	O
expressions	O
;	O
the	O
percent	O
sign	O
matches	O
zero	O
or	O
more	O
characters	O
,	O
and	O
underscore	O
a	O
single	O
character	O
.	O
</s>
<s>
Transact-SQL	B-Language
also	O
supports	O
square	O
brackets	O
(	O
and	O
)	O
to	O
list	O
sets	O
and	O
ranges	O
of	O
characters	O
to	O
match	O
,	O
a	O
leading	O
caret	O
negates	O
the	O
set	O
and	O
matches	O
only	O
a	O
character	O
not	O
within	O
the	O
list	O
.	O
</s>
<s>
In	O
Microsoft	B-Application
Access	I-Application
,	O
the	O
asterisk	B-Language
sign	O
matches	O
zero	O
or	O
more	O
characters	O
,	O
the	O
question	O
mark	O
matches	O
a	O
single	O
character	O
,	O
the	O
number	O
sign	O
matches	O
a	O
single	O
digit	O
(	O
0	O
–	O
9	O
)	O
,	O
and	O
square	O
brackets	O
can	O
be	O
used	O
for	O
sets	O
or	O
ranges	O
of	O
characters	O
to	O
match	O
.	O
</s>
<s>
In	O
regular	B-Language
expressions	I-Language
,	O
the	O
period	O
(	O
,	O
also	O
called	O
"	O
dot	O
"	O
)	O
is	O
the	O
wildcard	B-Algorithm
pattern	O
which	O
matches	O
any	O
single	O
character	O
.	O
</s>
<s>
Combined	O
with	O
the	O
asterisk	B-Language
operator	O
it	O
will	O
match	O
any	O
number	O
of	O
any	O
characters	O
.	O
</s>
<s>
In	O
this	O
case	O
,	O
the	O
asterisk	B-Language
is	O
also	O
known	O
as	O
the	O
Kleene	O
star	O
.	O
</s>
