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71 lines
2.7 KiB
Plaintext
71 lines
2.7 KiB
Plaintext
\section printf printf - display text according to a format string
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\subsection printf-synopsis Synopsis
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\fish{synopsis}
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printf format [argument...]
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\endfish
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\subsection printf-description Description
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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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\subsection printf-example Example
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\fish
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printf '%s\\t%s\\n' flounder fish
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\endfish
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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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\fish
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printf '%s: %d' "Number of bananas in my pocket" 42
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\endfish
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Will print "Number of bananas in my pocket: 42", _without_ a newline.
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