GREP_COLORS — ANSI colours for grep, ripgrep, ag

# Legacy — single colour for matched text only (pre-2007 grep):
export GREP_COLOR='01;31'                    # bold red match, only

# Current — per-slot, colours every output element independently:
export GREP_COLORS='mt=01;31:fn=35:ln=32:bn=32:se=36'
#   mt=01;31     matched text          → bold red
#   fn=35        filename prefix       → magenta
#   ln=32        line number prefix    → green
#   bn=32        byte offset prefix    → green
#   se=36        separator (: / -- )   → cyan

# Check which env is set:
env | grep -E '^GREP_COLOR'

# If both are set, GREP_COLORS wins — drop the legacy one to avoid confusion:
unset GREP_COLOR

# All 11 GREP_COLORS slots, set explicitly:
export GREP_COLORS='\
mt=01;31:\
ms=01;31:\
mc=01;31:\
fn=35:\
ln=32:\
bn=32:\
se=36:\
sl=:\
cx=:\
rv:\
ne'

# What each slot does:
#   mt   matched text on EITHER selected or context line — shorthand
#        for setting ms + mc to the same value
#   ms   matched text on a selected line       (default: 01;31 bold red)
#   mc   matched text on a context line        (default: 01;31 bold red)
#   fn   filename prefix                       (default: 35 magenta)
#   ln   line number prefix (-n)               (default: 32 green)
#   bn   byte offset prefix (-b)               (default: 32 green)
#   se   separator (: between fn/ln/match; --
#        between groups; - in context output)  (default: 36 cyan)
#   sl   the entire selected (matching) line   (default: empty = inherit)
#   cx   the entire context line (-A/-B/-C)    (default: empty = inherit)
#   rv   boolean — swaps sl<->cx when -v       (default: off)
#   ne   boolean — skip Erase-In-Line escape   (default: off)

# Truecolor since grep 3.0+ (no real version gate — passes bytes through):
export GREP_COLORS='mt=38;2;255;128;0;01:fn=38;5;213:ln=38;5;120'
#   mt=38;2;255;128;0;01    match → bold truecolor orange
#   fn=38;5;213             filename → 256-palette pink
#   ln=38;5;120             line number → 256-palette mint

# Verify by piping a small file through it:
printf 'one\ntwo\nthree\n' | grep --color=always two

# Three modes:
grep --color=auto   pattern file       # TTY only (the sensible default)
grep --color=always pattern file       # force through pipes
grep --color=never  pattern file       # disable entirely
grep --color        pattern file       # bare flag = auto
NO_COLOR=1 grep     pattern file       # universal opt-out (grep 3.5+)

# Canonical aliases — drop into ~/.bashrc / ~/.zshrc:
alias grep='grep --color=auto'
alias egrep='egrep --color=auto'
alias fgrep='fgrep --color=auto'

# Force colour into a pager that renders SGR:
grep --color=always -rn pattern src/ | less -R

# Force colour into an HTML converter for blog / code review:
grep --color=always -rn TODO src/ | aha > todos.html

# Defeat the alias for one invocation (use the binary directly):
\\grep pattern file             # bypasses alias
command grep pattern file        # same
/usr/bin/grep pattern file       # explicit path

# British spelling — same flag, same behaviour:
grep --colour=always pattern file

# One-shot — override match colour to bright yellow on red background:
rg --colors 'match:fg:yellow' \
   --colors 'match:bg:red' \
   --colors 'match:style:bold' \
   pattern src/

# All four element types:
rg --colors 'path:fg:magenta'        \
   --colors 'path:style:bold'        \
   --colors 'line:fg:green'          \
   --colors 'line:style:nointense'   \
   --colors 'column:fg:cyan'         \
   --colors 'match:fg:red'           \
   --colors 'match:style:bold'       \
   pattern src/

# Truecolor (0xRRGGBB form):
rg --colors 'match:fg:0xff8000' \
   --colors 'match:style:bold' \
   pattern src/

# 256 palette:
rg --colors 'match:fg:256' \
   --colors 'match:fg:208' \
   pattern src/

# Persist via ~/.ripgreprc (one flag per line, no quotes):
cat > ~/.ripgreprc <<'EOF'
--colors=match:fg:yellow
--colors=match:bg:red
--colors=match:style:bold
--colors=path:fg:magenta
--colors=line:fg:green
--smart-case
EOF
echo 'export RIPGREP_CONFIG_PATH="$HOME/.ripgreprc"' >> ~/.bashrc

# Color modes — note 'ansi' is the Windows-emit-anyway variant:
rg --color=auto   pattern        # default — TTY only
rg --color=always pattern        # force through pipe (Unix-style ANSI)
rg --color=ansi   pattern        # force ANSI even on Windows (skip console API)
rg --color=never  pattern        # disable
NO_COLOR=1 rg     pattern        # honoured

# One-shot — override match colour to bright red bg + bold white fg:
ag --color-match='1;37;41' pattern src/

# All three element flags together:
ag --color-line-number='1;36' \
   --color-match='1;37;41' \
   --color-path='1;35' \
   pattern src/

# 256-palette + truecolor (ag passes bytes through, no validation):
ag --color-match='38;5;208;01' pattern src/                    # palette orange
ag --color-match='38;2;255;128;0;01' pattern src/              # 24-bit orange

# Toggle colour (no =value form for these flags):
ag --color   pattern src/       # force on
ag --nocolor pattern src/       # force off
NO_COLOR=1 ag pattern src/      # universal opt-out (honoured)

# Persist via ~/.agrc — one flag per line, NO leading -- and NO quotes:
cat > ~/.agrc <<'EOF'
--color-line-number=1;36
--color-match=1;37;41
--color-path=1;35
--smart-case
--hidden
EOF

# Verify ag is picking it up:
ag --help 2>&1 | grep -E 'color|agrc'

# WRONG — the inner grep sees SGR bytes split across the substring,
# the match silently fails:
ls --color=always | grep '.conf'
git log --color=always --oneline | grep 'TODO'

# RIGHT (1) — inner grep with --color=never strips colour BEFORE matching:
ls --color=always | grep --color=never '.conf'
git log --color=always --oneline | grep --color=never 'TODO'

# RIGHT (2) — strip SGR with sed before the inner grep sees it:
ls --color=always | sed -E 's/\x1b\[[0-9;]*m//g' | grep '.conf'

# RIGHT (3) — use --color=auto (the default) and trust TTY detection,
# the OUTER command will skip colour because the pipe is not a TTY:
ls --color=auto | grep '.conf'                # ls strips colour automatically
git log --oneline | grep 'TODO'               # git pager also off when piped

# Symptom check — if you suspect SGR is leaking into a grep, decode it:
cmd --color=always | head -c 200 | cat -v
# look for ^[[31m / ^[[0m sequences — those are SGR bytes

# General-purpose ansi-strip wrapper (drop into ~/.bashrc):
strip_ansi() { sed -E 's/\x1b\[[0-9;]*[a-zA-Z]//g; s/\x1b\][^\x07]*\x07//g'; }
# Usage: ls --color=always | strip_ansi | grep '.conf'

# ~/.bashrc (Linux) or ~/.bash_profile (macOS Terminal.app):
export GREP_COLORS='mt=01;33;41:fn=35:ln=32:bn=32:se=36'
export RIPGREP_CONFIG_PATH="$HOME/.ripgreprc"
alias grep='grep --color=auto'
alias egrep='egrep --color=auto'
alias fgrep='fgrep --color=auto'

# ~/.zshrc / ~/.zprofile (macOS default since 10.15):
export GREP_COLORS='mt=01;33;41:fn=35:ln=32:bn=32:se=36'
export RIPGREP_CONFIG_PATH="$HOME/.ripgreprc"
alias grep='grep --color=auto'

# ~/.config/fish/config.fish — set -gx is global-export:
set -gx GREP_COLORS 'mt=01;33;41:fn=35:ln=32:bn=32:se=36'
set -gx RIPGREP_CONFIG_PATH ~/.ripgreprc
alias grep 'grep --color=auto'

# ~/.cshrc / ~/.tcshrc — setenv, no = sign:
setenv GREP_COLORS 'mt=01;33;41:fn=35:ln=32:bn=32:se=36'
setenv RIPGREP_CONFIG_PATH ~/.ripgreprc
alias grep 'grep --color=auto'

# ~/.ripgreprc — one flag per line, no quotes:
cat > ~/.ripgreprc <<'EOF'
--colors=match:fg:yellow
--colors=match:bg:red
--colors=match:style:bold
--colors=path:fg:magenta
--colors=line:fg:green
EOF

# ~/.agrc — same one-flag-per-line, NO leading -- in some versions
# (always test with: ag --color-match='1;33' pattern . 2>&1 | head):
cat > ~/.agrc <<'EOF'
--color-line-number=1;36
--color-match=1;33;41
--color-path=1;35
EOF

# macOS double-trap reminder — these only run on LOGIN shell:
#   ~/.bash_profile, ~/.zprofile, ~/.profile
# These only run on NON-login (subshell) shell:
#   ~/.bashrc, ~/.zshrc
# Terminal.app spawns login shells; iTerm2 + VS Code terminal default
# to non-login. Source one from the other for symmetry:
#   echo '[ -r ~/.bashrc ] && . ~/.bashrc' >> ~/.bash_profile