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diff --git a/doc/gawktexi.in b/doc/gawktexi.in index d2b24312..d8e9654f 100644 --- a/doc/gawktexi.in +++ b/doc/gawktexi.in @@ -44,6 +44,14 @@ @set MINUS @end ifdocbook +@iftex +@set TIMES @times +@end iftex +@ifnottex +@set TIMES * +@end ifnottex + + @set xref-automatic-section-title @c The following information should be updated here only! @@ -2943,14 +2951,59 @@ it is worth addressing. @cindex Brink, Jeroen The ``shells'' on Microsoft Windows systems use the double-quote character for quoting, and make it difficult or impossible to include an -escaped double-quote character in a command-line script. -The following example, courtesy of Jeroen Brink, shows -how to print all lines in a file surrounded by double quotes: +escaped double-quote character in a command-line script. The following +example, courtesy of Jeroen Brink, shows how to escape the double quotes +from this one liner script that prints all lines in a file surrounded by +double quotes: + +@example +@{ print "\"" $0 "\"" @} +@end example + +@noindent +In an MS-Windows command-line the one-liner script above may be passed as +follows: @example gawk "@{ print \"\042\" $0 \"\042\" @}" @var{file} @end example +In this example the @samp{\042} is the octal code for a double-quote; +@command{gawk} converts it into a real double-quote for output by +the @code{print} statement. + +In MS-Windows escaping double-quotes is a little tricky because you use +backslashes to escape double-quotes, but backslashes themselves are not +escaped in the usual way; indeed they are either duplicated or not, +depending upon whether there is a subsequent double-quote. The MS-Windows +rule for double-quoting a string is the following: + +@enumerate +@item +For each double quote in the orginal string, let @var{N} be the number +of backslash(es) before it, @var{N} might be zero. Replace these @var{N} +backslash(es) by @math{2@value{TIMES}@var{N}+1} backslash(es) + +@item +Let @var{N} be the number of backslash(es) tailing the original string, +@var{N} might be zero. Replace these @var{N} backslash(es) by +@math{2@value{TIMES}@var{N}} backslash(es) + +@item +Surround the resulting string by double-quotes. +@end enumerate + +So to double-quote the one-liner script @samp{@{ print "\"" $0 "\"" @}} +from the previous example you would do it this way: + +@example +gawk "@{ print \"\\\"\" $0 \"\\\"\" @}" @var{file} +@end example + +@noindent +However, the use of @samp{\042} instead of @samp{\\\"} is also possible +and easier to read, because backslashes that are not followed by a +double-quote don't need duplication. @node Sample Data Files @section @value{DDF}s for the Examples |