gray

#!/bin/sh
help() {
  self="${0##*/}"
  echo "Gray standard output, leaving standard error nice and visible."
  echo "Usage: $self [-c|--color[=WHEN]] [CAT_OPTIONS] [FILE...]"
  echo "   or: COMMAND | $self [OPTIONS]"
  echo ""
  echo '  -c, --color[=WHEN]  Use colors. As `-c` or `--color`, WHEN=`always`'
  echo '                      WHEN may be `always`, `auto` (default) or `never`'
  echo ""
  version
}

version() {
  echo "Part of misc-scripts: https://github.com/adamhotep/misc-scripts"
  echo "gray 2.0.20240519.0 Copyright 2003+ by Adam Katz, GPL v2+"
  exit
}

if [ -n "$NO_COLOR" ]; then
  color=never
elif [ -n "$CLICOLOR_FORCE" ]; then
  color=always
else
  color=auto
fi

case "$1" in
  ( -h | --help )		help ;;
  ( --col*r=?* )		color="${1#*=}"; shift ;;
  ( -c | -color | --colo* )	color=always; shift ;;
  ( -c?* )			color="${1#c}"; shift ;;
  ( -V | --version )		version ;;
esac

# disabled colors or auto and not a TTY
if [ "$color" != "${color#[n0]}" ] \
|| [ "${color#auto}" != "${color#[Tt][Tt][Yy]}" -a ! -t 1 ]; then
  exec cat "$@"
fi

if [ "$#" -gt 0 ]; then
  # Arguments were given. Files, hopefully. Parse with `cat` and re-run `gray`
  cat "$@" |exec "$0"
else
  # for every line, print the output with gray SGR codes, resetting at the end
  while IFS= read -r line; do
    printf '\033[1;30m%s\033[m\n' "$line"
  done
fi

# test with this call from bash:
# (echo stdout;sleep 1;echo stderr>&2;sleep 1;echo stdout)|gray