Bash Activity Indicator

spinner.sh

#!/usr/bin/env bash

#
# A simple activity indicator for bash scripting.
# Optional message can be passed to spinner function.
# This can be used on interactive shells and in scripts
#
# Scripting usage:
#
# e_spinner "Import MySQL"
# cat somefile.sql | mysql > /dev/null
# e_spinner_end
#
# Interactive Shell Usage:
# e_spinner_start "Slow running command"; sleep 10; e_spinner_end
#

e_spinner() {
  local spinstr='⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏'
  while sleep 0.1; do
    e_reset_line
    local temp=${spinstr#?}
    printf " %s${RESET} ${2}%b${RESET}" "${spinstr:0:1}" "${1}"
    local spinstr=$temp${spinstr%"$temp"}
  done
}

e_spinner_start() {
  local MESSAGE="$1"
  e_spinner "$MESSAGE" &
  E_SPINNER_PID=$!
  disown $E_SPINNER_PID &> /dev/null #make sure bash doesn't freak out when we kill the spinner
}

e_spinner_end() {
  kill $E_SPINNER_PID &> /dev/null
  e_reset_line
}