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NOTE: When using the integer format-control letters for values that are outside the range of a C?long?integer,?gawk?switches to the?%g?format specifier. If?--lint?is provided on the command line?gawk?warns about this. Other versions of?awk?may print invalid values or do something else entirely.
Optional,additional parameters may lie between the?%?and the control letter:
| Description |
count$
count’th argument at this point in the formatting. This is called a?positional specifier?and is intended primarily for use in translated versions of format strings,not in the original text of an AWK program. It is a?gawk?extension.spacewidthprec
The dynamic?width?and?prec?capabilities of the?ANSI?C?printf()?routines are supported. A*?in place of either the?width?or?prec?specifications causes their values to be taken from the argument list to?printf?or?sprintf(). To use a positional specifier with a dynamic width or precision,supply the?count$?after the?*?in the format string. For example,"%3$*2$.*1$s".
Special File Names
When doing I/O redirection from either?print?or?printf?into a file,or via?getline?from a file,?gawk?recognizes certain special filenames internally. These filenames allow access to open file descriptors inherited from?gawk’s parent process (usually the shell). These file names may also be used on the command line to name data files. The filenames are:
| Description |
n
n.These are particularly useful for error messages. For example:
print "You blew it!" > "/dev/stderr"
whereas you would otherwise have to use
print "You blew it!" | "cat 1>&2" （编辑：ASP站长）
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