加班中，在调研函数计算，使用nodejs做一个demo的时候，在比较深的路径下下载了一张图片。

不想用finder逐层文件夹寻找，而是希望直接打开，顺手敲了一下open 1.png命令，果然打开了。

which open看一下位置，果然是mac系统自带，位于/usr/bin/open。

open -h查看提示：

demo $ open -h
Warning: Xcode platforms folder not found at "/Library/Developer/CommandLineTools". You may have invalid DEVELOPER_DIR or stale xcode-select setting.
Usage: open [-e] [-t] [-f] [-W] [-R] [-n] [-g] [-h] [-s ][-b ] [-a ] [filenames] [--args arguments]
Help: Open opens files from a shell.
      By default, opens each file using the default application for that file.  
      If the file is in the form of a URL, the file will be opened as a URL.
Options: 
      -a                Opens with the specified application.
      -b                Opens with the specified application bundle identifier.
      -e                Opens with TextEdit.
      -t                Opens with default text editor.
      -f                Reads input from standard input and opens with TextEdit.
      -F  --fresh       Launches the app fresh, that is, without restoring windows. Saved persistent state is lost, excluding Untitled documents.
      -R, --reveal      Selects in the Finder instead of opening.
      -W, --wait-apps   Blocks until the used applications are closed (even if they were already running).
          --args        All remaining arguments are passed in argv to the application's main() function instead of opened.
      -n, --new         Open a new instance of the application even if one is already running.
      -j, --hide        Launches the app hidden.
      -g, --background  Does not bring the application to the foreground.
      -h, --header      Searches header file locations for headers matching the given filenames, and opens them.
      -s                For -h, the SDK to use; if supplied, only SDKs whose names contain the argument value are searched.
                        Otherwise the highest versioned SDK in each platform is used.

根据提示内容，可知open就是从命令行执行打开。包括本地文件和远程文件（浏览器打开）。

关于使用参数和一些常用的应用、网站等打开方式：

1、 open -a

open -a qq

2、打开网页

open https://www.zhihu.com/

3、open -f

从标准输入中读取输入内容，并通过文本编辑器打开。

示例： ls |open -f

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