diff options
Diffstat (limited to 'doc/gawk.texi')
| -rw-r--r-- | doc/gawk.texi | 134 |
1 files changed, 73 insertions, 61 deletions
diff --git a/doc/gawk.texi b/doc/gawk.texi index 1dd75e51..63489dae 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -3289,8 +3289,8 @@ The following list describes @command{gawk}-specific options: @table @code @item -b @itemx --characters-as-bytes -@cindex @code{-b} option -@cindex @code{--characters-as-bytes} option +@cindex @option{-b} option +@cindex @option{--characters-as-bytes} option Cause @command{gawk} to treat all input data as single-byte characters. In addition, all output written with @code{print} or @code{printf} are treated as single-byte characters. @@ -3304,8 +3304,8 @@ multibyte characters. This option is an easy way to tell @command{gawk}: @item -c @itemx --traditional -@cindex @code{-c} option -@cindex @code{--traditional} option +@cindex @option{-c} option +@cindex @option{--traditional} option @cindex compatibility mode (@command{gawk}), specifying Specify @dfn{compatibility mode}, in which the GNU extensions to the @command{awk} language are disabled, so that @command{gawk} behaves just @@ -3316,17 +3316,17 @@ which summarizes the extensions. Also see @item -C @itemx --copyright -@cindex @code{-C} option -@cindex @code{--copyright} option +@cindex @option{-C} option +@cindex @option{--copyright} option @cindex GPL (General Public License), printing Print the short version of the General Public License and then exit. @item -d@r{[}@var{file}@r{]} @itemx --dump-variables@r{[}=@var{file}@r{]} -@cindex @code{-d} option -@cindex @code{--dump-variables} option -@cindex @code{awkvars.out} file -@cindex files, @code{awkvars.out} +@cindex @option{-d} option +@cindex @option{--dump-variables} option +@cindex @file{awkvars.out} file +@cindex files, @file{awkvars.out} @cindex variables, global, printing list of Print a sorted list of global variables, their types, and final values to @var{file}. If no @var{file} is provided, print this @@ -3345,8 +3345,8 @@ names like @code{i}, @code{j}, etc.) @item -D@r{[}@var{file}@r{]} @itemx --debug=@r{[}@var{file}@r{]} -@cindex @code{-D} option -@cindex @code{--debug} option +@cindex @option{-D} option +@cindex @option{--debug} option @cindex @command{awk} debugging, enabling Enable debugging of @command{awk} programs (@pxref{Debugging}). @@ -3358,8 +3358,8 @@ No space is allowed between the @option{-D} and @var{file}, if @item -e @var{program-text} @itemx --source @var{program-text} -@cindex @code{-e} option -@cindex @code{--source} option +@cindex @option{-e} option +@cindex @option{--source} option @cindex source code, mixing Provide program source code in the @var{program-text}. This option allows you to mix source code in files with source @@ -3370,8 +3370,8 @@ programs (@pxref{AWKPATH Variable}). @item -E @var{file} @itemx --exec @var{file} -@cindex @code{-E} option -@cindex @code{--exec} option +@cindex @option{-E} option +@cindex @option{--exec} option @cindex @command{awk} programs, location of @cindex CGI, @command{awk} scripts for Similar to @option{-f}, read @command{awk} program text from @var{file}. @@ -3401,8 +3401,8 @@ with @samp{#!} scripts (@pxref{Executable Scripts}), like so: @item -g @itemx --gen-pot -@cindex @code{-g} option -@cindex @code{--gen-pot} option +@cindex @option{-g} option +@cindex @option{--gen-pot} option @cindex portable object files, generating @cindex files, portable object, generating Analyze the source program and @@ -3413,8 +3413,8 @@ for information about this option. @item -h @itemx --help -@cindex @code{-h} option -@cindex @code{--help} option +@cindex @option{-h} option +@cindex @option{--help} option @cindex GNU long options, printing list of @cindex options, printing list of @cindex printing, list of options @@ -3439,8 +3439,8 @@ find the main source code via the @option{-f} option or on the command-line. @item -l @var{lib} @itemx --load @var{lib} -@cindex @code{-l} option -@cindex @code{--load} option +@cindex @option{-l} option +@cindex @option{--load} option @cindex loading, library Load a shared library @var{lib}. This searches for the library using the @env{AWKLIBPATH} environment variable. The correct library suffix for your platform will be @@ -3451,8 +3451,8 @@ a shared library. @item -L @r{[}value@r{]} @itemx --lint@r{[}=value@r{]} -@cindex @code{-l} option -@cindex @code{--lint} option +@cindex @option{-l} option +@cindex @option{--lint} option @cindex lint checking, issuing warnings @cindex warnings, issuing Warn about constructs that are dubious or nonportable to @@ -3474,16 +3474,16 @@ care to search for all occurrences of each inappropriate construct. As @item -M @itemx --bignum -@cindex @code{-M} option -@cindex @code{--bignum} option +@cindex @option{-M} option +@cindex @option{--bignum} option Force arbitrary precision arithmetic on numbers. This option has no effect if @command{gawk} is not compiled to use the GNU MPFR and MP libraries (@pxref{Arbitrary Precision Arithmetic}). @item -n @itemx --non-decimal-data -@cindex @code{-n} option -@cindex @code{--non-decimal-data} option +@cindex @option{-n} option +@cindex @option{--non-decimal-data} option @cindex hexadecimal values@comma{} enabling interpretation of @cindex octal values@comma{} enabling interpretation of @cindex troubleshooting, @code{--non-decimal-data} option @@ -3498,15 +3498,15 @@ Use with care. @item -N @itemx --use-lc-numeric -@cindex @code{-N} option -@cindex @code{--use-lc-numeric} option +@cindex @option{-N} option +@cindex @option{--use-lc-numeric} option Force the use of the locale's decimal point character when parsing numeric input data (@pxref{Locales}). @item -o@r{[}@var{file}@r{]} @itemx --pretty-print@r{[}=@var{file}@r{]} -@cindex @code{-o} option -@cindex @code{--pretty-print} option +@cindex @option{-o} option +@cindex @option{--pretty-print} option Enable pretty-printing of @command{awk} programs. By default, output program is created in a file named @file{awkprof.out}. The optional @var{file} argument allows you to specify a different @@ -3516,16 +3516,16 @@ No space is allowed between the @option{-o} and @var{file}, if @item -O @itemx --optimize -@cindex @code{--optimize} option -@cindex @code{-O} option +@cindex @option{--optimize} option +@cindex @option{-O} option Enable some optimizations on the internal representation of the program. At the moment this includes just simple constant folding. The @command{gawk} maintainer hopes to add more optimizations over time. @item -p@r{[}@var{file}@r{]} @itemx --profile@r{[}=@var{file}@r{]} -@cindex @code{-p} option -@cindex @code{--profile} option +@cindex @option{-p} option +@cindex @option{--profile} option @cindex @command{awk} profiling, enabling Enable profiling of @command{awk} programs (@pxref{Profiling}). @@ -3540,8 +3540,8 @@ in the left margin, and function call counts for each function. @item -P @itemx --posix -@cindex @code{-P} option -@cindex @code{--posix} option +@cindex @option{-P} option +@cindex @option{--posix} option @cindex POSIX mode @cindex @command{gawk}, extensions@comma{} disabling Operate in strict POSIX mode. This disables all @command{gawk} @@ -3590,8 +3590,8 @@ also issues a warning if both options are supplied. @item -r @itemx --re-interval -@cindex @code{-r} option -@cindex @code{--re-interval} option +@cindex @option{-r} option +@cindex @option{--re-interval} option @cindex regular expressions, interval expressions and Allow interval expressions (@pxref{Regexp Operators}) @@ -3602,8 +3602,8 @@ and for use in combination with the @option{--traditional} option. @item -S @itemx --sandbox -@cindex @code{-S} option -@cindex @code{--sandbox} option +@cindex @option{-S} option +@cindex @option{--sandbox} option @cindex sandbox mode Disable the @code{system()} function, input redirections with @code{getline}, @@ -3615,16 +3615,16 @@ can't access your system (other than the specified input data file). @item -t @itemx --lint-old -@cindex @code{-L} option -@cindex @code{--lint-old} option +@cindex @option{-L} option +@cindex @option{--lint-old} option Warn about constructs that are not available in the original version of @command{awk} from Version 7 Unix (@pxref{V7/SVR3.1}). @item -V @itemx --version -@cindex @code{-V} option -@cindex @code{--version} option +@cindex @option{-V} option +@cindex @option{--version} option @cindex @command{gawk}, versions of, information about@comma{} printing Print version information for this particular copy of @command{gawk}. This allows you to determine if your copy of @command{gawk} is up to date @@ -5043,8 +5043,8 @@ These sequences are: @item Collating symbols Multicharacter collating elements enclosed between @samp{[.} and @samp{.]}. For example, if @samp{ch} is a collating element, -then @code{[[.ch.]]} is a regexp that matches this collating element, whereas -@code{[ch]} is a regexp that matches either @samp{c} or @samp{h}. +then @samp{[[.ch.]]} is a regexp that matches this collating element, whereas +@samp{[ch]} is a regexp that matches either @samp{c} or @samp{h}. @cindex bracket expressions, equivalence classes @item Equivalence classes @@ -5052,7 +5052,7 @@ Locale-specific names for a list of characters that are equal. The name is enclosed between @samp{[=} and @samp{=]}. For example, the name @samp{e} might be used to represent all of -``e,'' ``@`e,'' and ``@'e.'' In this case, @code{[[=e=]]} is a regexp +``e,'' ``@`e,'' and ``@'e.'' In this case, @samp{[[=e=]]} is a regexp that matches any of @samp{e}, @samp{@'e}, or @samp{@`e}. @end table @@ -5096,7 +5096,7 @@ or underscores (@samp{_}): @item \s Matches any whitespace character. Think of it as shorthand for -@w{@code{[[:space:]]}}. +@w{@samp{[[:space:]]}}. @c @cindex operators, @code{\S} (@command{gawk}) @cindex backslash (@code{\}), @code{\S} operator (@command{gawk}) @@ -5104,7 +5104,7 @@ Think of it as shorthand for @item \S Matches any character that is not whitespace. Think of it as shorthand for -@w{@code{[^[:space:]]}}. +@w{@samp{[^[:space:]]}}. @c @cindex operators, @code{\w} (@command{gawk}) @cindex backslash (@code{\}), @code{\w} operator (@command{gawk}) @@ -5112,7 +5112,7 @@ Think of it as shorthand for @item \w Matches any word-constituent character---that is, it matches any letter, digit, or underscore. Think of it as shorthand for -@w{@code{[[:alnum:]_]}}. +@w{@samp{[[:alnum:]_]}}. @c @cindex operators, @code{\W} (@command{gawk}) @cindex backslash (@code{\}), @code{\W} operator (@command{gawk}) @@ -5120,7 +5120,7 @@ letter, digit, or underscore. Think of it as shorthand for @item \W Matches any character that is not word-constituent. Think of it as shorthand for -@w{@code{[^[:alnum:]_]}}. +@w{@samp{[^[:alnum:]_]}}. @c @cindex operators, @code{\<} (@command{gawk}) @cindex backslash (@code{\}), @code{\<} operator (@command{gawk}) @@ -5231,7 +5231,7 @@ are allowed. @item @code{--traditional} Traditional Unix @command{awk} regexps are matched. The GNU operators are not special, and interval expressions are not available. -The POSIX character classes (@code{[[:alnum:]]}, etc.) are supported, +The POSIX character classes (@samp{[[:alnum:]]}, etc.) are supported, as Brian Kernighan's @command{awk} does support them. Characters described by octal and hexadecimal escape sequences are treated literally, even if they represent regexp metacharacters. @@ -5857,21 +5857,27 @@ BEGIN @{ RS = "\0" @} # whole file becomes one record? @command{gawk} in fact accepts this, and uses the @sc{nul} character for the record separator. However, this usage is @emph{not} portable -to other @command{awk} implementations. +to most other @command{awk} implementations. @cindex dark corner, strings, storing -All other @command{awk} implementations@footnote{At least that we know +Almost all other @command{awk} implementations@footnote{At least that we know about.} store strings internally as C-style strings. C strings use the @sc{nul} character as the string terminator. In effect, this means that @samp{RS = "\0"} is the same as @samp{RS = ""}. @value{DARKCORNER} +It happens that recent versions of @command{mawk} can use the @sc{nul} +character as a record separator. However, this is a special case: +@command{mawk} does not allow embedded @sc{nul} characters in strings. + @cindex records, treating files as @cindex files, as single records The best way to treat a whole file as a single record is to simply read the file in, one record at a time, concatenating each record onto the end of the previous ones. +@c @strong{FIXME}: Using @sc{nul} is good for @file{/proc/environ} etc. + @docbook </sidebar> @end docbook @@ -5902,20 +5908,26 @@ BEGIN @{ RS = "\0" @} # whole file becomes one record? @command{gawk} in fact accepts this, and uses the @sc{nul} character for the record separator. However, this usage is @emph{not} portable -to other @command{awk} implementations. +to most other @command{awk} implementations. @cindex dark corner, strings, storing -All other @command{awk} implementations@footnote{At least that we know +Almost all other @command{awk} implementations@footnote{At least that we know about.} store strings internally as C-style strings. C strings use the @sc{nul} character as the string terminator. In effect, this means that @samp{RS = "\0"} is the same as @samp{RS = ""}. @value{DARKCORNER} +It happens that recent versions of @command{mawk} can use the @sc{nul} +character as a record separator. However, this is a special case: +@command{mawk} does not allow embedded @sc{nul} characters in strings. + @cindex records, treating files as @cindex files, as single records The best way to treat a whole file as a single record is to simply read the file in, one record at a time, concatenating each record onto the end of the previous ones. + +@c @strong{FIXME}: Using @sc{nul} is good for @file{/proc/environ} etc. @end cartouche @end ifnotdocbook @c ENDOFRANGE inspl @@ -10105,7 +10117,7 @@ point when reading the @command{awk} program source code, and for command-line variable assignments (@pxref{Other Arguments}). However, when interpreting input data, for @code{print} and @code{printf} output, and for number to string conversion, the local decimal point character is used. -@value{DARKCORNER}. +@value{DARKCORNER} Here are some examples indicating the difference in behavior, on a GNU/Linux system: @@ -34088,7 +34100,7 @@ The option for raw sockets was removed, since it was never implemented (@pxref{TCP/IP Networking}). @item -Ranges of the form @code{[d-h]} are treated as if they were in the +Ranges of the form @samp{[d-h]} are treated as if they were in the C locale, no matter what kind of regexp is being used, and even if @option{--posix} (@pxref{Ranges and Locales}). @@ -34296,7 +34308,7 @@ When @command{gawk} switched to using locale-aware regexp matchers, the problems began; especially as both GNU/Linux and commercial Unix vendors started implementing non-ASCII locales, @emph{and making them the default}. Perhaps the most frequently asked question became something -like ``why does @code{[A-Z]} match lowercase letters?!?'' +like ``why does @samp{[A-Z]} match lowercase letters?!?'' This situation existed for close to 10 years, if not more, and the @command{gawk} maintainer grew weary of trying to explain that |