If you regularly use the command line and want to directly open an application and pass a file to it you can use the following:
open -a TextEdit ~/Documents/myfile.txt
The switch -a says use this application:
More switches from the command line:
open --help -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). -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. --args All remaining arguments are passed in argv to the application's main() function instead of opened.