The standard text editor.
If the named
file does not exist, ed creates it;
otherwise, the existing
file is opened for editing.
As a line editor, ed is generally
no longer used because vi and ex have superseded it.
Some utilities, such as diff, continue to make use of ed.
Encryption can be used only in the United States.
Same as -x, but assume
file began in encrypted form.
string as the prompt for commands (default is
The P command turns the prompt display on and off.
Suppress character counts, diagnostics, and the ! prompt for shell commands.
Supply a key to encrypt or decrypt
file using crypt.