在手册页中搜索特定选项

Question

我经常发现自己man正在执行命令只是为了了解一个特定选项。大多数情况下，我可以很好地搜索该选项，除非它是类似的东西，ffmpeg或者gcc我必须遍历大约 40 个匹配项才能找到该选项的实际描述......

有时我可以很幸运地搜索“选项”这个词来接近，然后从那里改进它，但如果我能可靠地直接跳到有问题的选项，那就太好了。如果有一种工具可以解析选项并构建一个可以进行搜索的数据库，那将会很酷，但是在查看了几页的 groff 标记后，我确定这只是一种最佳猜测由于 groff 标记中缺少元信息......在我理想的世界中，emacs 中的女性模式将支持搜索特定选项...... :)

直接跳转到手册页中的特定选项的任何提示？

Answer 1

这是我的脚本来做到这一点。就叫他。

#!/bin/sh
# he - print brief help about a single option or command
# Mikel Ward <mikel@mikelward.com>

# Example Usage:
# he bash continue
# he rsync -v

scriptname=he

usage()
{
    cat <<EOF 1>&2
Usage: $scriptname <command> [<option|section>]
Example:
    $scriptname bash getopts (shows documentation for bash getopts)
    $scriptname ssh -v       (shows documentation for ssh -v flag)
    $scriptname select       (shows SYNOPSIS for select(2))
    $scriptname 'open(2)'    (shows SYNOPSIS for open(2))
EOF
}

if test $# -lt 1; then
    usage
    exit 2
fi

manpage="$1"
# show the SYNOPSIS section if no section or option was given
option="${2:-SYNOPSIS}"

# handle manpage(number)
case $manpage in *\(*\))
    page=${manpage%\(*\)}
    section=${manpage#$page}
    section=${section#\(}
    section=${section%\)}
    manpage=$page
    ;;
esac

man ${section:+-s $section} "$manpage" | perl -n -e '
BEGIN {
    $option = "'$option'";
    $inside_option = 0;
}
if (!$inside_option) {
    if (/^(\s*)\Q$option\E\b/p) {
        # start of this option
        $option_indentation = $1;
        $inside_option = 1;
        $saw_blank_line = 0;
        print;
    }
} else {
    if (/^$/) {
        $saw_blank_line = 1;
        print;
    } elsif (/^\Q$option_indentation\E\S/ and $saw_blank_line) {
        # item at same indentation => start of next option
        $inside_option = 0;
    } elsif (/^\S/) {
        # new heading => start of next section
        $inside_option = 0;
    } else {
        print;
    }
}
'

$ he cp    
SYNOPSIS
       cp [OPTION]... [-T] SOURCE DEST
       cp [OPTION]... SOURCE... DIRECTORY
       cp [OPTION]... -t DIRECTORY SOURCE...

$ he gcc -dD
       -dD Dump all macro definitions, at the end of preprocessing, in addition to normal output.

$ he rsync -v
        -v, --verbose               increase verbosity

$ he bash getopts
       getopts optstring name [args]
              getopts is used by shell procedures to parse positional parameters.  optstring contains the option characters to be recognized; if a character is  followed  by  a  colon,  the  option  is
              expected  to  have  an  argument, which should be separated from it by white space.  The colon and question mark characters may not be used as option characters.  Each time it is invoked,
              getopts places the next option in the shell variable name, initializing name if it does not exist, and the index of the next argument to be processed into the variable OPTIND.  OPTIND  is
              initialized  to  1 each time the shell or a shell script is invoked.  When an option requires an argument, getopts places that argument into the variable OPTARG.  The shell does not reset
              OPTIND automatically; it must be manually reset between multiple calls to getopts within the same shell invocation if a new set of parameters is to be used.

              When the end of options is encountered, getopts exits with a return value greater than zero.  OPTIND is set to the index of the first non-option argument, and name is set to ?.

              getopts normally parses the positional parameters, but if more arguments are given in args, getopts parses those instead.

              getopts can report errors in two ways.  If the first character of optstring is a colon, silent error reporting is used.  In normal operation diagnostic messages are printed  when  invalid
              options or missing option arguments are encountered.  If the variable OPTERR is set to 0, no error messages will be displayed, even if the first character of optstring is not a colon.

              If  an  invalid  option  is  seen, getopts places ? into name and, if not silent, prints an error message and unsets OPTARG.  If getopts is silent, the option character found is placed in
              OPTARG and no diagnostic message is printed.

              If a required argument is not found, and getopts is not silent, a question mark (?) is placed in name, OPTARG is unset, and a diagnostic message is printed.  If getopts is silent, then  a
              colon (:) is placed in name and OPTARG is set to the option character found.

              getopts returns true if an option, specified or unspecified, is found.  It returns false if the end of options is encountered or an error occurs.

但是，如果您无权访问这样的脚本，只需运行less，然后键入/^ *-option（注意空格），例如，在gcc手册页中，键入/^ *-dDEnter以查找该-dD选项的文档。

这是有效的，因为该选项通常出现在行的开头。