Git colour config — color.ui, slots, pager, --color=always

# Inspect current value (auto = sane default).
git config --get color.ui

# The sane default — emit colour on TTY, strip on pipe:
git config --global color.ui auto

# Force colour through pipes (for piping into less -R, see snippet 6):
git config --global color.ui always

# Disable globally (e.g. dumb terminal, log scraping, or accessibility):
git config --global color.ui never
# or honour the universal env var (git respects NO_COLOR since 2.21):
NO_COLOR=1 git diff

# Per-command keys, all default to value of color.ui:
git config --global color.diff        auto
git config --global color.status      auto
git config --global color.branch      auto
git config --global color.grep        auto
git config --global color.interactive auto
git config --global color.decorate    auto     # git log --decorate
git config --global color.pager       true     # respect color when paged
git config --global color.advice      auto     # hint messages
git config --global color.push        auto     # since git 2.41
git config --global color.remote      auto     # since git 2.21

# Example: force colour for diff specifically, leave everything else auto:
git config --global color.diff always

# git diff slots — most commonly retuned for readability:
git config --global color.diff.meta       "yellow bold"
git config --global color.diff.frag       "magenta bold"
git config --global color.diff.func       "cyan"
git config --global color.diff.context    "white"
git config --global color.diff.old        "red bold"
git config --global color.diff.new        "green bold"
git config --global color.diff.whitespace "red reverse"
git config --global color.diff.commit     "yellow"

# git status slots:
git config --global color.status.header    "white"
git config --global color.status.added     "green"
git config --global color.status.updated   "green"
git config --global color.status.changed   "yellow"
git config --global color.status.untracked "red"
git config --global color.status.branch    "cyan bold"
git config --global color.status.nobranch  "red reverse"

# git branch slots:
git config --global color.branch.current  "green bold"
git config --global color.branch.local    "white"
git config --global color.branch.remote   "yellow"
git config --global color.branch.upstream "magenta"
git config --global color.branch.plain    "white"

# git grep slots (git 2.0+):
git config --global color.grep.filename     "magenta"
git config --global color.grep.linenumber   "yellow"
git config --global color.grep.match        "red bold"
git config --global color.grep.matchContext "white"
git config --global color.grep.separator    "white"

# Truecolor (git 2.26+, 2020):
git config --global color.diff.new "#3fb950 bold"
git config --global color.diff.old "#f85149 bold"

# git log --decorate slots:
git config --global color.decorate.branch       "green bold"
git config --global color.decorate.remoteBranch "red bold"
git config --global color.decorate.tag          "yellow bold"
git config --global color.decorate.stash        "magenta bold"
git config --global color.decorate.HEAD         "cyan bold"
git config --global color.decorate.grafted      "blue"

# Pair with a one-line graph to make refs even more legible:
git config --global alias.lg \
    "log --graph --oneline --decorate --all"
# Then: git lg

# ~/.bashrc — fully-coloured git prompt
# (Debian / Ubuntu / Fedora ship git-prompt.sh under
# /usr/share/git-core/contrib/completion/git-prompt.sh;
# Homebrew ships it under
# /opt/homebrew/etc/bash_completion.d/git-prompt.sh.)

source /usr/share/git/completion/git-prompt.sh

# Colour hints: branch (green) / dirty (yellow) / staged (red).
export GIT_PS1_SHOWCOLORHINTS=1
# Show + for staged changes, * for unstaged.
export GIT_PS1_SHOWDIRTYSTATE=1
# Show $ if anything is stashed.
export GIT_PS1_SHOWSTASHSTATE=1
# Show % if there are untracked files.
export GIT_PS1_SHOWUNTRACKEDFILES=1
# Show ↑/↓ counts vs upstream.
export GIT_PS1_SHOWUPSTREAM="auto verbose"

# \[ ... \] tells bash these bytes are zero-width — required
# for correct line-edit wrap math. PROMPT_COMMAND lets
# __git_ps1 splice the git status into PS1 each prompt.
PROMPT_COMMAND='__git_ps1 "\[\e[36m\]\u\[\e[0m\]@\[\e[35m\]\h\[\e[0m\]:\[\e[34m\]\w\[\e[0m\]" "\\\$ "'

# zsh equivalent (~/.zshrc) — drops \[ \] (zsh uses %{...%}):
# setopt PROMPT_SUBST
# source /usr/share/git/completion/git-prompt.sh
# PROMPT='%F{cyan}%n%f@%F{magenta}%m%f:%F{blue}%~%f$(__git_ps1 " (%s)") %# '

# Inspect current pager (most systems: 'less').
git config --get core.pager

# Sane explicit form — leaves colour intact, quits on short output:
git config --global core.pager "less -FRX"

# Or set LESS globally and leave core.pager unset:
export LESS=FRX                              # add to ~/.bashrc

# Custom pager — REMEMBER to set the flags yourself:
git config --global core.pager "less -+F -+X -R"   # don't auto-quit

# Disable the pager entirely (one-shot):
git --no-pager log

# Per-command pager override:
git config --global pager.diff "delta --side-by-side"   # ships colour itself
git config --global pager.log  "less -FRX +'/^commit'"  # jump to first commit
git config --global pager.branch false                  # no pager for branch -a

# Pipe coloured log into less manually (with -R to render SGR):
git log --color=always --graph --oneline | less -R

# Same idea with diff — useful with side-by-side viewers:
git diff --color=always | bat --paging=always

# Convert coloured diff to HTML for a code review email / blog post:
git log --color=always --graph -p HEAD~5..HEAD | aha > review.html

# Pipe coloured log into tee, keep on screen AND save to file:
git log --color=always --oneline | tee --output-error=warn /tmp/log.ansi
# Strip later when archiving (see /strip):
sed -E 's/\x1b\[[0-9;]*m//g' /tmp/log.ansi > /tmp/log.txt

# fzf with coloured input — needs --ansi flag:
git log --color=always --oneline | fzf --ansi