Vertical Line Markers

Suppose you type a lot in the terminal, and I bet you do. Some commands may have inconveniently long output and you need a way to conveniently scroll the terminal viewport up to the top of that command. This is what this feature is there for. You can easily walk up/down your markers like you'd walk up code folds or markers in VIM or other editors.

Set a mark

A mark is set by the OSC 133 ; A shell-integration sequence, which says "a new prompt starts on this line":

printf "\033]133;A\033\\"

Note

Contour used to offer a dedicated SETMARK sequence (CSI > M) for this. It was deprecated in favour of OSC 133 ; A and removed in 0.7.1 — OSC 133 ; A does the same thing and, unlike a Contour-only extension, is understood by other terminals too.

You will usually not write this by hand: Contour's bundled shell integration already emits it (along with the rest of OSC 133), which is what also drives "copy last command output" and output folding. Install it with:

contour generate integration shell zsh to ~/.config/contour/shell-integration.zsh

Example key bindings in Contour

input_mapping:
    - { mods: [Alt, Shift], key: 'k', mode: '~Alt', action: ScrollMarkUp }
    - { mods: [Alt, Shift], key: 'j', mode: '~Alt', action: ScrollMarkDown }

If you would rather integrate the mark into your prompt by hand than install the shell integration, the sections below show how.

Integration into ZSH

zsh is way too configurable to give a fully generic answer here, but to show how you can integrate vertical line markers when using powerlevel9k, this is what your ~/.zshrc config could contain:

prompt_setmark() {
    echo -ne "%{\033]133;A\033\\\\%}"
}
POWERLEVEL9K_LEFT_PROMPT_ELEMENTS=(setmark user dir vcs)

Integration into Bash

Bash is usually highly customized to your needs, but the bottom line would be as suggested below. You can create your custom prompt_setmark function that contains \\[ and \\] as enclosing markers for the escape sequence to tell your shell that they do not change the current cursor position, and then use this function in our PS1 environment variable or invoked inside your function assigned to PROMPT_COMMAND.

prompt_setmark() {
    echo -ne "\\[\033]133;A\033\\\\\\]"
}

# extending existing PS1
export PS1="`prompt_setmark`${PS1}"