mjhjmtu

Why bother?

Clearing scrollback buffer is handy in many ways, for example, when I wish to run some command with long output, and want to quickly scroll to start of this output. When scrollback buffer is cleared, I can just scroll to top, and will be done.

Some considerations:

There is clear command, according to man,

clear clears your screen if this is possible, including its scrollback buffer (if the extended "E3" capability is defined).

In gnome-terminal clear does not clear scrollback buffer. (What is "E3" capability, though?)

There is also reset, which clears, but it does a little bit more than that, and it is really slow (on my system it takes more than a second, which is significant delay for humans to be noticed).

And there is echo -ne 'ec' or echo -ne '33c', which does the job. And indeed it is much faster than reset.

The question is, what is ec sequence, how it differs from what clear and reset does, and why there is no separate command for it?

There is also readline's C-l key sequence, which by default bound to clear-screen command (I mean, readline command, not shell command). What is this command? Which escape sequence it emits? How does it actually work? Does it run shell command? Or what? Again, in gnome-terminal, it seems like it works just by spiting out blank lines until prompt appear in top line of terminal. Not sure about other terminal emulators. This is very cumbersome behavior. It pollutes scrollback with chunks of emptiness, so you must scroll up more, and more. It is like a hack, rather than clean solution.

Another question is, is there a readline command for mentioned ec sequence? I want to bound it to C-l instead because I always want to clear scrollback buffer when I clear the screen.

And another question is how to just type such escape sequence into terminal, to perform desired action? Then do not have to think about binding C-l to another readline command (if such command exists). I tried typing Esc, then c but this does not work.

UPDATE
This question answered mostly here: https://unix.stackexchange.com/a/375784/257159. It is very good answer which explains almost all questions asked here.

Many terminal emulators use the same escape sequences as XTerm, or similar. For XTerm, Escc is defined as "Full Reset (RIS)". It seems reasonable that a full reset would clear the scrollback buffer.

I have had no success using readline to bind to the sequence itself, but a workaround is

bind '"C-l": "C-aC-kprintf "\033c"C-m"'

This has some caveats. First, it puts the printf command in your shell history, which is not ideal. Second, it cannot be used while inputting a command; it overwrites the current input line.