The shell session

Once your login completes, you see your normal shell prompt (for example, $ or >). This is a UNIX interface, not the 3270-type interface that is displayed by the OMVS command. By default, the terminal interface is in line mode (also known as canonical mode), which means that each time you type a command at the prompt, you need to press Enter to process the command. Some utilities switch the terminal interface to raw mode. When you use a raw mode utility (such as vi or talk), or when command line editing is enabled in the shell, each keystroke is transmitted; you do not need to press <Enter>.

When you are in a shell session, you can:

Run all shell commands and utilities.
Run any application from the z/OS UNIX file system.
Use the vi editor and other full-screen applications such as talk and more.

In the z/OS UNIX environment, the asynchronous terminal interface session has some differences from an OMVS session:

You cannot switch to TSO/E. However, you can use the tso shell command to run a TSO/E command from your session.
You cannot use the ISPF editor. (This includes the oedit and TSO/E OEDIT commands, which invoke ISPF File Edit.)