为什么 Debian 没有 time(1) 联机帮助页？

Question

搜索time命令的联机帮助页不会产生任何结果（搜索表单）。

作为旁注，它似乎是一个 BASH 内置命令，因为dpkg --search bin/time找不到它。也许这些命令没有自己的联机帮助页？

Answer 1

正确的，通常 shell 内置程序有help页面，因为它们的使用通常不涉及。如果内置命令是那么复杂，就可能已经被推送的功能集成到其自身的可执行文件，此时它简化外壳逻辑的努力会得到男人页面。

您可以time通过使用获取信息help time

[jadavis6@ditirlns01 ~]$ help time
time: time [-p] PIPELINE
    Execute PIPELINE and print a summary of the real time, user CPU time,
    and system CPU time spent executing PIPELINE when it terminates.
    The return status is the return status of PIPELINE.  The `-p' option
    prints the timing summary in a slightly different format.  This uses
    the value of the TIMEFORMAT variable as the output format.
times: times
    Print the accumulated user and system times for processes run from
    the shell.

由于您的示例是bash，对于 GNU 工具，您还可以尝试info <toolName>获取更详尽的信息。help旨在在命令行上运行，并且他们不想淹没您的屏幕（可能将有用的信息推送到屏幕外），因此他们尽量保持help简短并在信息页面中为您提供完整的信息。例如：

[jadavis6@hypervisor ~]$ info time

<...在我按下回车键后，会出现一个 ncurses 页面...>

File: time.info,  Node: Top,  Prev: (dir),  Up: (dir)

   This file documents the the GNU `time' command for running programs
and summarizing the system resources they use.  This is edition 1.7,
for version 1.7.

* Menu:

* Resource Measurement::  Measuring program resource use.

 -- The Detailed Node Listing --

Measuring Program Resource Use

* Setting Format::      Selecting the information reported by `time'.
* Format String::       The information `time' can report.
* Redirecting::         Writing the information to a file.
* Examples::            Examples of using `time'.
* Accuracy::            Limitations on the accuracy of `time' output.
* Invoking time::       Summary of the options to the `time' command.

The Format String

* Time Resources::
* Memory Resources::
* I/O Resources::
* Command Info::

完整描述信息页面可能超出了您的问题范围，因此我将就此搁置。我只是提到它，所以你知道他们的存在。