You may content yourself with double-clicking on files to open them, but depending on what you're doing, there may be a quicker or more convenient option. Here are 19 different ways to get the job done:
Double-click on a file.
Select a file and press command-down arrow.
Select a file and press command-O.
Click on a file in the Finder sidebar.
Drag a file onto a program icon in the Finder, in the sidebar, in the Finder toolbar, or in the Dock.
Open a file using an Open dialog box by selecting the file and then clicking on Open or OK.
From an Open dialog box, drag a file onto a program icon in the Finder, the sidebar, or the Dock.
Drag a file, or a file's proxy icon (in the title bar), from the Finder to an Open dialog box, and then select it and click on Open or OK.
Control-click, or right-click, on a file and then choose Open or Open With. In the contextual menu, select an application. This is a good way to open a file with a program you don't usually use (for example, with Adobe Acrobat instead of Preview). This works for files in Finder windows or in the sidebar.
If you have a stack in the Dock, click on the stack to display its contents, and then click on a file to open it.
Select a file in the Finder, press command-I, and then double-click on the file's preview. (You may need to expand the Preview section of the Info window.)
If you're in Column view, double-click on a file's preview in the Preview column, if it's visible.
If you're in Cover Flow view, double-click on a file's Cover Flow preview.
If you're viewing a file in Quick Look, double-click on it, and then press command-O or press command-down arrow.
Search for a file in the Spotlight menu (press command-space bar to activate it, and then type your search term), select a file in the list, and then press return or enter.
If you've used a file recently, select Apple menu: Recent Items: filename..
In Terminal, run the following command: open filename. Make sure to include the path to the file with its name, for example: /Users/kirk/Documents/my_file.
In Terminal, run the following command to open a file with a specific application: open applicationname filename. With this command, include the path to the application and the file--for example: open /Applications/TextEdit /Users/kirk/Documents/my_file.
In Safari, type a file's path using the following format, and then press enter: file:///Users/username/Documents/filename.
This story, "Nineteen Ways to Open a File" was originally published by Macworld.