GIT_PAGER environment variable must either not be set at all, or set to the value
delta (you can add argument here if you want; this env var plays the same role as the
core.pager config entry).
A pager is a program that accepts many lines of text as input, and displays them one screenful at a time.
The standard pager is less, and this is what delta uses by default (it's also what
It is very important that you are using a recent version of less. In particular, on Windows, the installed version of less is often broken and it is usually necessary to install it yourself or use the version of less that is installed with git on Windows.
The command line flags passed to
lessare important, and there are some environment variables that affect these (see below). By default, delta will try to ensure that they are sensible.
When delta is displaying lengthy output, anything you do with the keyboard or mouse is actually received by less, and it is worth looking at less documentation (
man lessor online) to discover what you can do.
The exact command that
delta uses to start its pager is taken from one of the following environment variables (in this order):
Delta does not use
bat when it is running, and delta users do not need to
install bat. (Delta does use the
bat Rust library for its syntax highlighting
themes and language definitions, and for launching the pager, which is why the
BAT_PAGER environment variable is honored).
If none of these is set, delta uses
less -R, and you should always include
-R if you are setting these environment variables yourself.
In addition to those
*PAGER environment variables, the behavior of
less is also affected by the
LESS environment variable (see
man less or online documentation). This env var can contain command line options and/or interactive less-commands (prefixed by a leading
+ sign; these are executed every time right after less is launched).
To temporarily activate and inactivate delta features, you can use
export DELTA_FEATURES='+side-by-side my-feature'
+ means "add these features to those configured in git config".)
DELTA_PAGER env var is described above.