coat

#!/bin/bash
# @Function
# cat lines colorfully. coat means *CO*lorful c*AT*.
#
# @Usage
#   $ echo -e 'Hello\nWorld' | coat
#   $ coat /path/to/file1
#   $ coat /path/to/file1 /path/to/file2
#
# @online-doc https://github.com/oldratlee/useful-scripts/blob/dev-2.x/docs/shell.md#-coat
# @author Jerry Lee (oldratlee at gmail dot com)
set -eEuo pipefail

# if not in console, use cat directly
#   check isatty in bash https://stackoverflow.com/questions/10022323
[ ! -t 1 ] && exec cat "$@"

readonly -a ROTATE_COLORS=(33 35 36 31 32 37 34)
COUNT=0
rotateColorPrint() {
  local message="$*"

  # skip color for white space
  if [[ "$message" =~ ^[[:space:]]*$ ]]; then
    printf '%s\n' "$message"
  else
    local color="${ROTATE_COLORS[COUNT++ % ${#ROTATE_COLORS[@]}]}"
    printf "\033[1;${color}m%s\033[0m\n" "$message"
  fi
}

# Bash read line does not read leading spaces
# https://stackoverflow.com/questions/29689172
cat "$@" | while IFS= read -r line; do
  rotateColorPrint "$line"
done