whatis（显示简短的手册页描述）_语法_示例_Unix&Linux命令

在类似Unix的操作系统上，whatis命令显示简短的手册页描述。

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Unix&Linux

每个手册页中都有简短说明。whatis搜索手册页名称并显示匹配的任何名称的手册页描述。

名称可以包含通配符（-w）或为正则表达式（-r）。使用这些选项，可能有必要使用名称引号或转义（\）特殊字符以阻止外壳程序解释它们。

索引数据库在搜索过程中使用，并由mandb程序更新。根据您的安装，此操作可以通过定期的cron作业运行，也可以在安装新的手册页后手动运行。要从相对索引数据库生成旧样式的文本whatis数据库，请发出以下命令：

什么是-M manpath -w'*'| 排序> manpath / whatis

...其中manpath是手动页面层次结构，例如/ usr / man。

Each manual page has a short description available within it. whatis searches the manual page names and displays the manual page descriptions of any name matched.

name may contain wildcards (-w) or be a regular expression (-r). Using these options, it may be necessary to quote the name or escape (\) the special characters to stop the shell from interpreting them.

Index databases are used during the search and are updated by the mandb program. Depending on your installation, this may be run by a periodic cron job or may be run manually after new manual pages have been installed. To produce an old style text whatis database from the relative index database, issue the below command:

whatis -M manpath -w '*' | sort > manpath/whatis

...where manpath is a manual page hierarchy such as /usr/man.

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whatis [-dlhvV] [-r|-w] [-s list] [-m system[,...]] [-M path] [-L locale] 
       [-C file] name ...

选件

-d，--debug	打印调试信息。
-v，-- verbose	打印详细警告消息。
-r，-- regex	将每个名称解释为正则表达式。如果名称与页面名称的任何部分匹配，则将进行匹配。由于数据库搜索的性质，此选项会使whatis变慢。
-w，--wildcard	将每个名称解释为包含外壳样式通配符的模式。为了进行匹配，扩展名称必须与整个页面名称匹配。由于数据库搜索的性质，此选项会使whatis变慢。
-l，--long	不要将输出调整为端子宽度。正常情况下，输出将被截断为终端宽度，以避免NAME部分写得不好得出的丑陋结果。
-s list，-- sections list，-- section list	仅搜索给定的手册部分。该列表是用冒号或逗号分隔的部分列表。如果列表中的条目是一个简单的部分，例如“ 3 ”，则显示的描述列表将包括“ 3 ”，“ 3perl ”，“ 3x ”等部分中的页面；等等。而如果列表中的条目具有扩展名，例如“ 3perl ”，则列表将仅包含手册部分中该部分的页面。
-m system [ ， ...]，-- systems = system [ ， ...]	如果此系统有权访问其他操作系统的手册页名称，则可以使用此选项进行访问。要搜索NewOS的手册页名称，请使用选项“ -m NewOS ”。指定的系统可以是逗号分隔的操作系统名称的组合。要包括对本机操作系统的手册页名称的搜索，请在参数字符串中包括系统名称man。此选项将覆盖$ SYSTEM环境变量。
-M path，-- manpath =path	指定另一组用冒号分隔的手动页面层次结构进行搜索。默认情况下，whatis使用$ MANPATH环境变量，除非它为空或未设置，在这种情况下，它将根据$ PATH环境变量确定适当的manpath 。此选项将覆盖$ MANPATH的内容。
-L locale，-- locale =locale	Whatis通常会通过调用C函数setlocale来确定您当前的语言环境，该函数会询问各种环境变量，可能包括$ LC_MESSAGES和$ LANG。要临时覆盖确定的值，请使用此选项将语言环境字符串直接提供给whatis。请注意，它只有在开始搜索页面后才会生效。诸如帮助消息之类的输出将始终显示在最初确定的语言环境中。
-C file，-- config-file =file	使用此用户配置文件，而不要使用默认的〜/ .manpath。
-h，--help	打印帮助消息并退出。
-V，-- version	显示版本信息。

退出状态：

0	成功执行程序。
1	用法，语法或配置文件错误。
2	操作错误。
16	未找到符合指定条件的任何内容。

环境

SYSTEM	如果设置了$ SYSTEM，它将具有与将其指定为-m选项的参数相同的效果。
MANPATH	如果设置了$ MANPATH，则其值将解释为使用冒号分隔的手动页面层次结构搜索路径。
MANWIDTH	如果设置了$ MANWIDTH，则将其值用作终端宽度（请参见--long选项）。如果未设置，则将使用ioctl（如果可用），$ COLUMNS的值来计算终端宽度，或者如果所有其他方法均失败，则使用80个字符。

whatis [-dlhvV] [-r|-w] [-s list] [-m system[,...]] [-M path] [-L locale] 
       [-C file] name ...

Options

-d, --debug	Print debugging information.
-v, --verbose	Print verbose warning messages.
-r, --regex	Interpret each name as a regular expression. If a name matches any part of a page name, a match will be made. This option causes whatis to be somewhat slower due to the nature of database searches.
-w, --wildcard	Interpret each name as a pattern containing shell style wildcards. For a match to be made, an expanded name must match the entire page name. This option causes whatis to be somewhat slower due to the nature of database searches.
-l, --long	Do not trim output to the terminal width. Normally, output will be truncated to the terminal width to avoid ugly results from poorly-written NAME sections.
-s list, --sections list, --section list	Search only the given manual sections. The list is a colon- or comma-separated list of sections. If an entry in list is a simple section, for example "3", then the displayed list of descriptions will include pages in sections "3", "3perl", "3x", and so on; while if an entry in list has an extension, for example "3perl", then the list will only include pages in that exact part of the manual section.
-m system[,...], --systems=system[,...]	If this system has access to other operating system's manual page names, they can be accessed using this option. To search NewOS's manual page names, use the option "-m NewOS". The system specified can be a combination of comma delimited operating system names. To include a search of the native operating system's manual page names, include the system name man in the argument string. This option will override the $SYSTEM environment variable.
-M path, --manpath=path	Specify an alternate set of colon-delimited manual page hierarchies to search. By default, whatis uses the $MANPATH environment variable, unless it is empty or unset, in which case it will determine an appropriate manpath based on your $PATH environment variable. This option overrides the contents of $MANPATH.
-L locale, --locale=locale	Whatis will normally determine your current locale by a call to the C function setlocale which interrogates various environment variables, possibly including $LC_MESSAGES and $LANG. To temporarily override the determined value, use this option to supply a locale string directly to whatis. Note that it will not take effect until the search for pages actually begins. Output such as the help message will always be displayed in the initially determined locale.
-C file, --config-file=file	Use this user configuration file rather than the default of ~/.manpath.
-h, --help	Print a help message and exit.
-V, --version	Display version information.

Exit Status:

0	Successful program execution.
1	Usage, syntax or configuration file error.
2	Operational error.
16	Nothing was found that matched the criteria specified.

Environment

SYSTEM	If $SYSTEM is set, it will have the same effect as if it had been specified as the argument to the -m option.
MANPATH	If $MANPATH is set, its value is interpreted as the colon-delimited manual page hierarchy search path to use.
MANWIDTH	If $MANWIDTH is set, its value is used as the terminal width (see the --long option). If it is not set, the terminal width will be calculated using an ioctl if available, the value of $COLUMNS, or falling back to 80 characters if all else fails.

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whatis whatis

显示一个什么样的描述whatis的。

whatis whatis

Display a description of what whatis is.

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