Manual Reference Pages - ENHANCE (1)
enhance - A program that adds command-line editing to third party programs.
enhance command [ argument ... ]
The enhance program provides enhanced command-line editing
facilities to users of third party applications, to which one doesnt
have any source code. It does this by placing a pseudo-terminal
between the application and the real terminal. It uses the tecla
command-line editing library to read input from the real terminal,
then forwards each just completed input line to the application via
the pseudo-terminal. All output from the application is forwarded
back unchanged to the real terminal.
Whenever the application stops generating output for more than a tenth
of a second, the enhance program treats the latest incomplete
output line as the prompt, and redisplays any incompleted input line
that the user has typed after it. Note that the small delay, which is
imperceptible to the user, isnt necessary for correct operation of
the program. It is just an optimization, designed to stop the input
line from being redisplayed so often that it slows down output.
Note that the user-level command-line editing facilities provided by
the Tecla library are documented in the tecla(7) man page
The one major problem that hasnt been solved yet, is how to deal with
applications that change whether typed input is echod by their
controlling terminal. For example, programs that ask for a password,
such as ftp and telnet, temporarily tell their controlling terminal
not to echo what the user types. Since this request goes to the
application side of the psuedo terminal, the enhance program has
no way of knowing that this has happened, and continues to echo typed
input to its controlling terminal, while the user types their
Furthermore, before executing the host application, the enhance
program initially sets the pseudo terminal to noecho mode, so that
everything that it sends to the program doesnt get redundantly
echoed. If a program that switches to noecho mode explicitly restores
echoing afterwards, rather than restoring the terminal modes that were
previously in force, then subsequently, every time that you enter a
new input line, a duplicate copy will be displayed on the next line.
libtecla.a - The tecla library.
~/.teclarc - The tecla personal customization file.
Martin Shepherd (firstname.lastname@example.org)
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