Using the `open` Command (with examples)

The open command in macOS allows users to open files, directories, and applications. It provides a convenient way to interact with various resources on a macOS system. In this article, we will explore several use cases of the open command and provide code examples for each scenario.

Use Case 1: Opening a File with the Associated Application

open file.ext

Motivation: This use case is handy when you want to open a specific file with its associated application. For example, you may want to open a document file using Pages or a video file using QuickTime Player.

Explanation: The open command with a file path as its argument opens the file using the default application associated with that file type.

Example Output: If you run open document.docx, it will open the “document.docx” file using the default application for viewing/editing Word documents, such as Microsoft Word or Pages.

Use Case 2: Running a Graphical macOS Application

open -a "Application"

Motivation: This command allows you to run a graphical macOS application directly from the terminal. It can be useful when you know the name of the application and want to launch it quickly.

Explanation: The -a option specifies the application name that you want to run. If there are spaces in the application name, enclose it in double quotes.

Example Output: Running open -a "Safari" will launch the Safari web browser.

Use Case 3: Running a Graphical macOS App Based on Bundle Identifier

open -b com.domain.application

Motivation: This use case is helpful when you want to run a specific macOS application based on its bundle identifier. Bundle identifiers are unique identifiers assigned to each application on macOS.

Explanation: The -b option specifies the bundle identifier of the application you want to run. To find out the bundle identifier of an application, you can use osascript or refer to the application’s documentation.

Example Output: For instance, running open -b com.apple.Safari will launch Safari using its bundle identifier.

Use Case 4: Opening the Current Directory in Finder

open .

Motivation: This command allows you to quickly open the current working directory in Finder, the file manager for macOS. You can use this to easily navigate through the directory structure or perform file operations using Finder’s graphical interface.

Explanation: The . refers to the current directory. By providing . as the argument to the open command, it opens the current directory in Finder.

Example Output: Running open . will open the current working directory in Finder.

Use Case 5: Revealing a File in Finder

open -R path/to/file

Motivation: If you have a file’s path but are unsure of its location in the filesystem, this command allows you to reveal and highlight the file in Finder, making it easier to locate.

Explanation: The -R option reveals the file in Finder and highlights it. Provide the full path to the file as an argument to the open command.

Example Output: open -R /Users/username/Documents/document.txt will open Finder and highlight the “document.txt” file in the “Documents” directory.

Use Case 6: Opening All Files of a Given Extension with the Associated Application

open *.ext

Motivation: If you have multiple files with the same file extension and want to open them simultaneously using their associated applications, this command is useful. It saves time by automatically opening all files with the provided extension.

Explanation: The * is a wildcard character that matches any characters, and .ext represents the file extension. Combining these allows opening all files in the current directory with the specified extension using their associated applications.

Example Output: If you run open *.txt, it will open all the text files in the current directory using the default text editor or associated application for viewing/editing text files.

Use Case 7: Opening a New Instance of an Application Specified via Bundle Identifier

open -n -b com.domain.application

Motivation: This command is useful if you want to open a new instance of a macOS application when one instance is already running. It allows you to run multiple instances of the same application concurrently.

Explanation: The -n option tells the open command to open a new instance of the application. This is useful when the application supports multiple windows or simultaneous instances. The -b option specifies the bundle identifier of the application you want to open.

Example Output: open -n -b com.apple.Safari will open a new instance of Safari, even if Safari is already running.

In this article, we explored various use cases of the open command in macOS and provided code examples for each scenario. With the ability to open files, directories, and applications with a single command, the open command is a versatile tool for macOS users.