текстовый редактор (text editor)
Описание (Description)
The ex utility is a line-oriented text editor. There are two
other modes of the editor—open and visual—in which screen-
oriented editing is available. This is described more fully by
the ex open and visual commands and in vi(1p).
If an operand is '-', the results are unspecified.
This section uses the term edit buffer to describe the current
working text. No specific implementation is implied by this term.
All editing changes are performed on the edit buffer, and no
changes to it shall affect any file until an editor command
writes the file.
Certain terminals do not have all the capabilities necessary to
support the complete ex definition, such as the full-screen
editing commands (visual mode or open mode). When these commands
cannot be supported on such terminals, this condition shall not
produce an error message such as ``not an editor command'' or
report a syntax error. The implementation may either accept the
commands and produce results on the screen that are the result of
an unsuccessful attempt to meet the requirements of this volume
of POSIX.1‐2017 or report an error describing the terminal-
related deficiency.
