Query: printf
OS: aix
Section: 3
Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar
Commands Reference, Volume 4, n - r
printf_Command
Purpose
Writes formatted output.
Syntax
printf Format [ Argument ... ]
Description
The printf command converts, formats, and writes its Argument
parameters
to standard output. The Argument parameters are formatted un-
der control of
the Format parameter. The formatted output line cannot exceed
LINE_MAX
bytes in length.
The following environment variables affect the execution of
the printf
command:
Determines the locale to use for the locale cate-
gories when
LANG both LC_ALL and the corresponding environment
variable
(beginning with LC_) do not specify a locale.
Determines the locale to be used to override any
values for
LC_ALL locale categories specified by the setting of LANG
or any
other LC_ environment variable.
Determines the locale for the interpretation of
sequences of
LC_CTYPE bytes of text data as characters; for example,
single versus
multibyte characters in parameters.
LC_MESSAGES Determines the language in which messages should
be written.
Determines the locale for numeric formatting. This
environment
LC_NUMERIC variable affects the format of numbers written us-
ing the e, E,
f, g, and G conversion characters.
The Format parameter is a character string that contains three
types of
objects:
* Plain characters copied to the output stream.
* Conversion specifications, each of which cause 0 or more
items to be
retrieved from the value parameter list.
* The following escape sequences. When copied to the output
stream,
these sequences cause their associated action to be dis-
played on
devices capable of the action:
Backslash
Alert
Backspace
Form feed
NCarriage return
Tab
Vertical tab
Where ddd is a one-, two-, or three-digit octal num-
ber.
dd These escape sequences are displayed as a byte with the
numeric value specified by the octal number.
The Argument parameter is a list of one or more strings to be
written to
standard output under the control of the Format parameter.
The Format parameter is reused as often as necessary to satis-
fy the
Argument parameters. Any extra c or s conversion specifica-
tions are
evaluated as if a null string Argument were supplied; other
extra
conversion specifications are evaluated as if a 0 Argument
were supplied.
Where the Format parameter contains no conversion specifica-
tions and
Argument parameters are present, the results are unspecified.
Each conversion specification in the Format parameter has the
following
syntax in this order:
1. A % (percent sign).
2. Zero or more options, which modify the meaning of the con-
version
specification. The option characters and their meanings
are:
- The result of the conversion is left-aligned within
the
field.
+ The result of a signed conversion always begins with
a
sign (+ or -).
If the first character of a signed conversion is not
a
blank sign, a blank is prefixed to the result. If both the
blank and + option characters are displayed, then
the
blank option character is ignored.
This option specifies that the value is to be con-
verted
to an alternate form. For c, d, i, u, and
s conversions, the option has no effect. For o
conversion, it increases the precision to force the
first
digit of the result to be a, 0 (zero). For x and
# X conversions, a nonzero result has 0x, or 0X
prefixed to it, respectively. For e, E, f,
g, and G conversions, the result always contains
a radix character, even if no digits follow the
radix
character. For g and G conversions, trailing zeros
are
not removed from the result as they usually are.
For d, i, o, u, x, e, E,
f, g, and G conversions, leading zeroes
(following any indication of sign or base) are used
to
0 pad to the field width, no space padding is per-
formed. If
the 0 (zero) and the - (minus sign) options are
displayed, the 0 (zero) option is ignored. For d, i,
o,
u, x, and X conversions, if a precision is speci-
fied,
the 0 (zero) option is ignored.
Note:
For other conversions, the behavior is undefined.
3. An optional decimal digit string that specifies the mini-
mum field
width. If the converted value has fewer characters than
the field
width, the field is padded on the left to the length spec-
ified by the
field width. If the left-adjustment option is specified,
the field is
padded on the right. If the result of a conversion is
wider than the
field width, the field is expanded to contain the convert-
ed result. No
truncation occurs. However, a small precision may cause
truncation on
the right.
4. An optional precision. The precision is a . (dot) followed
by a
decimal digit string. If no precision is given, it is
treated as 0
(zero). The precision specifies:
* The minimum number of digits to be displayed for the
d,
o, i, u, x, or X conversions.
* The number of digits to be displayed after the radix
character
for the e and f conversions.
* The maximum number of significant digits for the g
conversion.
* The maximum number of bytes to be printed from a
string in the
s conversion.
5. A character that indicates the type of conversion to be
applied, such
as:
% Performs no conversion. Prints a % (percent sign).
Accepts an integer value and converts it to signed
decimal
notation. The precision specifies the minimum number
of
digits to be displayed. If the value being converted
can
be represented in fewer digits, it is expanded with
d, i leading zeros. The default precision is 1. The result
of
converting a zero value with a precision of zero is a
null
string. Specifying a field width with a zero as a
leading
character causes the field width value to be padded
with
leading zeros.
Accepts an integer value and converts it to signed
octal
notation. The precision specifies the minimum number
of
digits to be displayed. If the value being converted
can
be represented in fewer digits, it is expanded with
o leading zeros. The default precision is 1. The result
of
converting a zero value with a precision of zero is a
null
string. Specifying a field width with a zero as a
leading
character causes the field width value to be padded
with
leading zeros. An octal value for field width is not
implied.
Accepts an integer value and converts it to unsigned
decimal notation. The precision specifies the minimum
number of digits to be displayed. If the value being
converted can be represented in fewer digits, it is
u expanded with leading zeros. The default precision is
1.
The result of converting a zero value with a preci-
sion of
zero is a null string. Specifying a field width with
a
zero as a leading character causes the field width
value
to be padded with leading zeros.
Accepts an integer value and converts it to hexadeci-
mal
notation. The letters abcdef are used for the x con-
version
and the letters ABCDEF are used for the X conversion.
The
precision specifies the minimum number of digits to
be
displayed. If the value being converted can be repre-
sented
x, X in fewer digits, it is expanded with leading zeros.
The
default precision is 1. The result of converting a
zero
value with a precision of zero is a null string.
Specifying a field width with a zero as a leading
character causes the field width value to be padded
with
leading zeros.
Accepts a float or double value and converts it to
decimal
notation in the format [-] ddd.ddd. The number of
digits
after the radix character (shown here as the decimal
f point) is equal to the precision specification. The
LC_NUMERIC locale category determines the radix char-
acter
to use tin this format. If no precision is specified,
then
six digits are output. If the precision is 0 (zero),
then
no radix character will be displayed.
Accepts a float or double value and converts it to
the
exponential form [-] d.dde{+|-}dd. There is one digit
before the radix character (shown here as the decimal
point) and the number of digits after the radix char-
acter
is equal to the precision specification. The LC_NU-
MERIC
locale category determines the radix character to use
tin
e, E this format. If no precision is specified, then six
digits
are output. If the precision is 0 (zero), then no
radix
character will be displayed. The E conversion charac-
ter
produces a number with E instead of e before the ex-
ponent.
The exponent always contains at least two digits.
However,
if the value to be printed requires an exponent
greater
than two digits, additional exponent digits are
printed as
necessary.
Accepts a float or double value and converts it in
the
style of the f or e conversion characters (or
E in the case of the G conversion), with the preci-
sion
specifying the number of significant digits. Trailing
g, G zeros are removed from the result. A radix character
is
displayed only if it is followed by a digit. The
style
used depends on the value converted. Style g results
only
if the exponent resulting from the conversion is less
than
-4, or if it is greater than or equal to the preci-
sion.
c Accepts a value as a string and prints the first
character
in the string.
Accepts a value as a string and prints characters
from the
string until the end of the string is encountered or
the
s number of characters indicated by the precision is
reached. If no precision is specified, all characters
up
to the first null character are printed.
Accepts a value as a string, that may contain
backslash-escape sequences. Bytes from the converted
b string are printed until the end of the string or
number
of bytes indicated by the precision specification is
reached. If the precision is omitted, all bytes until
the
first null character are printed.
The following backslash-escape sequences are supported:
* The escape sequences previously listed above under the de-
scription of
the Format parameter. These are converted to the individu-
al characters
they represented.
* The printf command to ignore any remaining charac-
ters in the string
parameter containing it, any remaining string parameters,
and any
additional characters in the Format parameter.
Exit Status
This command returns the following exit values:
0 Successful completion.
>0 An error occurred.
Examples
1. Enter the following command:
printf "%5d%4d0 1 21 321 4321 54321
This produces the following output:
1 21
3214321
54321 0
The Format parameter is used three times to print all of
the given
strings. The 0 (zero) is supplied by the printf command to
satisfy the
last %4d conversion specification.
2. Enter the following command:
printf "%c %c0 78 79
This produces the following output:
7 7
3. The following example demonstrates how the %$ format spec-
ifier can be
used to print the date in an order different from the or-
der of the
arguments:
printf (""%1$s, %3$d. %2$s, %4$d:%5$.2d", weekday,
month, day, hour, min);
Sunday, 3. July, 10:02
(weekday, day. month, hour:min)
Files
/usr/bin/printf Contains the printf command.
Related Information
The /usr/bin/echo command.
The printf subroutine in AIX 5L Version 5.3 Technical Refer-
ence: Base
Operating System and Extensions.
The Input and Output Handling Programmer's Overview in AIX 5L
Version
5.3 General Programming Concepts: Writing and Debugging Pro-
grams describes
the files, commands, and subroutines used for low-level,
stream, terminal,
and asynchronous I/O interfaces.
The National Language Support Overview in AIX 5L Version 5.3
National
Language Support Guide and Reference.
________________________________________________________________________________
Commands Reference, Volume 4, n - r
printf_Command
Purpose
Writes formatted output.
Syntax
printf Format [ Argument ... ]
Description
The printf command converts, formats, and writes its Argument
parameters
to standard output. The Argument parameters are formatted un-
der control of
the Format parameter. The formatted output line cannot exceed
LINE_MAX
bytes in length.
The following environment variables affect the execution of
the printf
command:
Determines the locale to use for the locale cate-
gories when
LANG both LC_ALL and the corresponding environment
variable
(beginning with LC_) do not specify a locale.
Determines the locale to be used to override any
values for
LC_ALL locale categories specified by the setting of LANG
or any
other LC_ environment variable.
Determines the locale for the interpretation of
sequences of
LC_CTYPE bytes of text data as characters; for example,
single versus
multibyte characters in parameters.
LC_MESSAGES Determines the language in which messages should
be written.
Determines the locale for numeric formatting. This
environment
LC_NUMERIC variable affects the format of numbers written us-
ing the e, E,
f, g, and G conversion characters.
The Format parameter is a character string that contains three
types of
objects:
* Plain characters copied to the output stream.
* Conversion specifications, each of which cause 0 or more
items to be
retrieved from the value parameter list.
* The following escape sequences. When copied to the output
stream,
these sequences cause their associated action to be dis-
played on
devices capable of the action:
Backslash
Alert
Backspace
Form feed
NCarriage return
Tab
Vertical tab
Where ddd is a one-, two-, or three-digit octal num-
ber.
dd These escape sequences are displayed as a byte with the
numeric value specified by the octal number.
The Argument parameter is a list of one or more strings to be
written to
standard output under the control of the Format parameter.
The Format parameter is reused as often as necessary to satis-
fy the
Argument parameters. Any extra c or s conversion specifica-
tions are
evaluated as if a null string Argument were supplied; other
extra
conversion specifications are evaluated as if a 0 Argument
were supplied.
Where the Format parameter contains no conversion specifica-
tions and
Argument parameters are present, the results are unspecified.
Each conversion specification in the Format parameter has the
following
syntax in this order:
1. A % (percent sign).
2. Zero or more options, which modify the meaning of the con-
version
specification. The option characters and their meanings
are:
- The result of the conversion is left-aligned within
the
field.
+ The result of a signed conversion always begins with
a
sign (+ or -).
If the first character of a signed conversion is not
a
blank sign, a blank is prefixed to the result. If both the
blank and + option characters are displayed, then
the
blank option character is ignored.
This option specifies that the value is to be con-
verted
to an alternate form. For c, d, i, u, and
s conversions, the option has no effect. For o
conversion, it increases the precision to force the
first
digit of the result to be a, 0 (zero). For x and
# X conversions, a nonzero result has 0x, or 0X
prefixed to it, respectively. For e, E, f,
g, and G conversions, the result always contains
a radix character, even if no digits follow the
radix
character. For g and G conversions, trailing zeros
are
not removed from the result as they usually are.
For d, i, o, u, x, e, E,
f, g, and G conversions, leading zeroes
(following any indication of sign or base) are used
to
0 pad to the field width, no space padding is per-
formed. If
the 0 (zero) and the - (minus sign) options are
displayed, the 0 (zero) option is ignored. For d, i,
o,
u, x, and X conversions, if a precision is speci-
fied,
the 0 (zero) option is ignored.
Note:
For other conversions, the behavior is undefined.
3. An optional decimal digit string that specifies the mini-
mum field
width. If the converted value has fewer characters than
the field
width, the field is padded on the left to the length spec-
ified by the
field width. If the left-adjustment option is specified,
the field is
padded on the right. If the result of a conversion is
wider than the
field width, the field is expanded to contain the convert-
ed result. No
truncation occurs. However, a small precision may cause
truncation on
the right.
4. An optional precision. The precision is a . (dot) followed
by a
decimal digit string. If no precision is given, it is
treated as 0
(zero). The precision specifies:
* The minimum number of digits to be displayed for the
d,
o, i, u, x, or X conversions.
* The number of digits to be displayed after the radix
character
for the e and f conversions.
* The maximum number of significant digits for the g
conversion.
* The maximum number of bytes to be printed from a
string in the
s conversion.
5. A character that indicates the type of conversion to be
applied, such
as:
% Performs no conversion. Prints a % (percent sign).
Accepts an integer value and converts it to signed
decimal
notation. The precision specifies the minimum number
of
digits to be displayed. If the value being converted
can
be represented in fewer digits, it is expanded with
d, i leading zeros. The default precision is 1. The result
of
converting a zero value with a precision of zero is a
null
string. Specifying a field width with a zero as a
leading
character causes the field width value to be padded
with
leading zeros.
Accepts an integer value and converts it to signed
octal
notation. The precision specifies the minimum number
of
digits to be displayed. If the value being converted
can
be represented in fewer digits, it is expanded with
o leading zeros. The default precision is 1. The result
of
converting a zero value with a precision of zero is a
null
string. Specifying a field width with a zero as a
leading
character causes the field width value to be padded
with
leading zeros. An octal value for field width is not
implied.
Accepts an integer value and converts it to unsigned
decimal notation. The precision specifies the minimum
number of digits to be displayed. If the value being
converted can be represented in fewer digits, it is
u expanded with leading zeros. The default precision is
1.
The result of converting a zero value with a preci-
sion of
zero is a null string. Specifying a field width with
a
zero as a leading character causes the field width
value
to be padded with leading zeros.
Accepts an integer value and converts it to hexadeci-
mal
notation. The letters abcdef are used for the x con-
version
and the letters ABCDEF are used for the X conversion.
The
precision specifies the minimum number of digits to
be
displayed. If the value being converted can be repre-
sented
x, X in fewer digits, it is expanded with leading zeros.
The
default precision is 1. The result of converting a
zero
value with a precision of zero is a null string.
Specifying a field width with a zero as a leading
character causes the field width value to be padded
with
leading zeros.
Accepts a float or double value and converts it to
decimal
notation in the format [-] ddd.ddd. The number of
digits
after the radix character (shown here as the decimal
f point) is equal to the precision specification. The
LC_NUMERIC locale category determines the radix char-
acter
to use tin this format. If no precision is specified,
then
six digits are output. If the precision is 0 (zero),
then
no radix character will be displayed.
Accepts a float or double value and converts it to
the
exponential form [-] d.dde{+|-}dd. There is one digit
before the radix character (shown here as the decimal
point) and the number of digits after the radix char-
acter
is equal to the precision specification. The LC_NU-
MERIC
locale category determines the radix character to use
tin
e, E this format. If no precision is specified, then six
digits
are output. If the precision is 0 (zero), then no
radix
character will be displayed. The E conversion charac-
ter
produces a number with E instead of e before the ex-
ponent.
The exponent always contains at least two digits.
However,
if the value to be printed requires an exponent
greater
than two digits, additional exponent digits are
printed as
necessary.
Accepts a float or double value and converts it in
the
style of the f or e conversion characters (or
E in the case of the G conversion), with the preci-
sion
specifying the number of significant digits. Trailing
g, G zeros are removed from the result. A radix character
is
displayed only if it is followed by a digit. The
style
used depends on the value converted. Style g results
only
if the exponent resulting from the conversion is less
than
-4, or if it is greater than or equal to the preci-
sion.
c Accepts a value as a string and prints the first
character
in the string.
Accepts a value as a string and prints characters
from the
string until the end of the string is encountered or
the
s number of characters indicated by the precision is
reached. If no precision is specified, all characters
up
to the first null character are printed.
Accepts a value as a string, that may contain
backslash-escape sequences. Bytes from the converted
b string are printed until the end of the string or
number
of bytes indicated by the precision specification is
reached. If the precision is omitted, all bytes until
the
first null character are printed.
The following backslash-escape sequences are supported:
* The escape sequences previously listed above under the de-
scription of
the Format parameter. These are converted to the individu-
al characters
they represented.
* The printf command to ignore any remaining charac-
ters in the string
parameter containing it, any remaining string parameters,
and any
additional characters in the Format parameter.
Exit Status
This command returns the following exit values:
0 Successful completion.
>0 An error occurred.
Examples
1. Enter the following command:
printf "%5d%4d0 1 21 321 4321 54321
This produces the following output:
1 21
3214321
54321 0
The Format parameter is used three times to print all of
the given
strings. The 0 (zero) is supplied by the printf command to
satisfy the
last %4d conversion specification.
2. Enter the following command:
printf "%c %c0 78 79
This produces the following output:
7 7
3. The following example demonstrates how the %$ format spec-
ifier can be
used to print the date in an order different from the or-
der of the
arguments:
printf (""%1$s, %3$d. %2$s, %4$d:%5$.2d", weekday,
month, day, hour, min);
Sunday, 3. July, 10:02
(weekday, day. month, hour:min)
Files
/usr/bin/printf Contains the printf command.
Related Information
The /usr/bin/echo command.
The printf subroutine in AIX 5L Version 5.3 Technical Refer-
ence: Base
Operating System and Extensions.
The Input and Output Handling Programmer's Overview in AIX 5L
Version
5.3 General Programming Concepts: Writing and Debugging Pro-
grams describes
the files, commands, and subroutines used for low-level,
stream, terminal,
and asynchronous I/O interfaces.
The National Language Support Overview in AIX 5L Version 5.3
National
Language Support Guide and Reference.
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