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81 lines
2.7 KiB
ReStructuredText
81 lines
2.7 KiB
ReStructuredText
printf - display text according to a format string
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==================================================
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Synopsis
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--------
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printf format [argument...]
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Description
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-----------
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printf formats the string FORMAT with ARGUMENT, and displays the result.
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The string FORMAT should contain format specifiers, each of which are replaced with successive arguments according to the specifier. Specifiers are detailed below, and are taken from the C library function ``printf(3)``.
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Unlike ``echo``, ``printf`` does not append a new line unless it is specified as part of the string.
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Valid format specifiers are:
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- ``%%d``: Argument will be used as decimal integer (signed or unsigned)
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- ``%%i``: Argument will be used as a signed integer
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- ``%%o``: An octal unsigned integer
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- ``%%u``: An unsigned decimal integer
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- ``%%x`` or ``%%X``: An unsigned hexadecimal integer
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- ``%%f``, ``%%g`` or ``%%G``: A floating-point number
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- ``%%e`` or ``%%E``: A floating-point number in scientific (XXXeYY) notation
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- ``%%s``: A string
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- ``%%b``: As a string, interpreting backslash escapes, except that octal escapes are of the form \0 or \0ooo.
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``%%`` signifies a literal "%".
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Note that conversion may fail, e.g. "102.234" will not losslessly convert to an integer, causing printf to print an error.
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printf also knows a number of backslash escapes:
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- ``\"`` double quote
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- ``\\`` backslash
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- ``\a`` alert (bell)
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- ``\b`` backspace
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- ``\c`` produce no further output
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- ``\e`` escape
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- ``\f`` form feed
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- ``\n`` new line
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- ``\r`` carriage return
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- ``\t`` horizontal tab
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- ``\v`` vertical tab
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- ``\ooo`` octal number (ooo is 1 to 3 digits)
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- ``\xhh`` hexadecimal number (hhh is 1 to 2 digits)
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- ``\uhhhh`` 16-bit Unicode character (hhhh is 4 digits)
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- ``\Uhhhhhhhh`` 32-bit Unicode character (hhhhhhhh is 8 digits)
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The ``format`` argument is re-used as many times as necessary to convert all of the given arguments. If a format specifier is not appropriate for the given argument, an error is printed. For example, ``printf '%d' "102.234"`` produces an error, as "102.234" cannot be formatted as an integer.
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This file has been imported from the printf in GNU Coreutils version 6.9. If you would like to use a newer version of printf, for example the one shipped with your OS, try ``command printf``.
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Example
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-------
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::
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printf '%s\\t%s\\n' flounder fish
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Will print "flounder fish" (separated with a tab character), followed by a newline character. This is useful for writing completions, as fish expects completion scripts to output the option followed by the description, separated with a tab character.
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::
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printf '%s: %d' "Number of bananas in my pocket" 42
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Will print "Number of bananas in my pocket: 42", _without_ a newline.
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