Getting information for items on disk, including details like creation and modification dates, labels, file sizes, and file type, can be useful when managing your files. The Finder contains a number of ways to view this information about files, which can be seen in different ways depending on the view options you are using in the Finder. In addition, the Finder information windows and some third-party options can be used to view and alter file attributes.
The file information that is available in the Finder will depend on the view being used.
In "List" and "Cover Flow" views, you will see a number of attributes for files and folders listed in columns next to the file name. By default, you will see the date modified, size, and kind of file listed, but you can customize the listings by enabling or disabling them in the "View Options" window.
The view options can be accessed from the "View" menu, or by pressing Command-J with the desired Finder window open. Keep in mind that the settings will be specific to the folder in the currently selected window (stored in the folder's hidden ".DS_Store" file) unless you click the "Use as Defaults" button.
In "Column" view, file information will only be shown in the Finder window when you select an individual file; selecting a folder will only show the contents of the folder. The view options for customizing the information shown in Column view are limited to either enabling or disabling the information column. Likewise, in Icon view you will be rather limited. There is a "Show Info" option in the view settings that you can enable, but this only lists the number of items within folders.
If you need more information than what is available directly in the Finder, you can use the Finder's "Info" window, which is available in any view mode. To get information, just select a file or folder and then either press Command-I, choose "Get Info" from the "File" menu, or choose the same option from the contextual menu by right-clicking a file.
While people may be familiar with this default information window in OS X, there are several options available for it. The first is the "Summary Info" window, which can be enabled by pressing the "Control" key when invoking the standard info window. This summary window allows for a single window to display the common attributes about a selection of files, instead of each file individually. If you want to get a lump sum of information on a selection of files in a folder, you can select the desired files and then press Control-Command-I and the system will present the combined information in the Summary Info window.
The next option in OS X is the Inspector, which is similar to the Summary Information window, with the exception that it works dynamically and stays above other applications as a floating window. This allows you to keep the window open and then choose different objects or selections of objects in the system and you will be able to instantly see the summary information on all of them. To see the inspector, just press the Option key (instead of the Control key for the Summary window) when invoking the standard information window.
While OS X has options for presenting a number of file attributes, the options and attributes shown are not the whole picture. Files may have numerous extended Finder attributes, permissions, encodings, and other details that some people may find useful to interact with. Since most users will not need these attributes, Apple does not include them in the Finder, but there are a few options people can use to access them.
If you are a Terminal user, there are various ways to get and set attributes for files, including the chown, chmod, ls, chflags, file, and stat commands. Beyond the Terminal, however, you can use custom info tools like FileXaminer or even full file-system browser replacements like Path Finder to get and set extended information on files in the system.