ex -- text editor

ex text editor	Command

SYNOPSIS

ex [-elRrsvx] [+command] [-c command] [-t tag] [-w size] [file ...]

ex is the line-editor mode of the Vi text editor. The ex internal commands are described in vi.

+command: begins the editing session by executing the specified editor command. To specify multiple commands, separate them with an or-bar (|).
-c command: begins editing by executing the specified editor command. You can specify multiple commands by separating them with an or-bar (|). command can be any ex command except those that enter input mode, such as insert or append.
-e: invokes ex. This option is intended for use with Vi.
-l: sets lisp mode. The ( and ) commands use blocks of lisp code as their context rather than sentences.
-R: sets read-only mode. To write over the original file, use the ! form of the command (for example, w!).
-r: recovers named files after an editor or system crash, or after a preserve command. If you don't specify a file argument, ex lists all recoverable files and exits.
-s: suppresses all interactive feedback except diagnostic messages. This is for batch mode operation: ex assumes the terminal cannot display text and ignores the value of TERM. ex also ignores all startup files and ignores the value of EXINIT.
-t tag: edits the file containing the specified tag and sets the virtual position in the edit buffer to point of definition for the tag (see ctags).
-v: invokes Vi.
-wsize: sets option variable window equal to size.
-x: uses encryption.

For further information, see vi.

POSIX.2. x/OPEN Portability Guide 4.0.

-e and -x are extensions to the POSIX standard. See the PORTABILITY section of the vi reference page.