spinner.sh

#!/bin/bash
CHECK_SYMBOL='\u2713'
X_SYMBOL='\u2A2F'

#
# Run the command passed as 1st argument and shows the spinner until this is done
#
# @param String $1 the command to run
# @param String $2 the title to show next the spinner
# @param var $3 the variable containing the return code
#
function execute_and_wait() {
  local __resultvar=$3

  eval $1 >/tmp/execute-and-wait.log 2>&1 &
  pid=$!
  delay=0.05

  frames=('\u280B' '\u2819' '\u2839' '\u2838' '\u283C' '\u2834' '\u2826' '\u2827' '\u2807' '\u280F')

  echo "$pid" >"/tmp/.spinner.pid"

  # Hide the cursor, it looks ugly :D
  tput civis
  index=0
  framesCount=${#frames[@]}
  while [ "$(ps a | awk '{print $1}' | grep $pid)" ]; do
    printf "${YELLOW}${frames[$index]}${NC} ${GREEN}$2${NC}"

    let index=index+1
    if [ "$index" -ge "$framesCount" ]; then
      index=0
    fi

    printf "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
    sleep $delay
  done


  #
  # Wait the command to be finished, this is needed to capture its exit status
  #
  wait $!
  exitCode=$?

  if [ "$exitCode" -eq "0" ]; then
    printf "${CHECK_SYMBOL} ${2}                                                                \b\n"
  else
    printf "${X_SYMBOL} ${2}                                                                \b\n"
  fi
  
  # Restore the cursor
  tput cnorm

  eval $__resultvar=$exitCode
}