Shell Programming and Scripting

v_time=12:12:12
correctTimeFlag=$(echo $v_time|awk '{for(i=1;i<=NF;i++) if( $i ~ /[0-2][0-9
]:[0-5][0-9]:[0-5][0-9]/){print i}}')

if [ correctTimeFlag -gt 0 ]
then
  echo "correct"
fi

correctTimeFlag=$(echo $v_time|awk '{for(i=1;i<=NF;i++) if( $i ~ /[0-2][0-9
]:[0-5][0-9]:[0-5][0-9]/){print i}}')

correctTimeFlag=$( chkTimeFormat $v_time)

 
chkTimeFormat()
{
 time="$1"
 echo "$time" | grep -v "^[0-2][0-9]:[0-5][0-9]:[0-5][0-9]$" >/dev/null && echo "0" || echo "1"
}

case $v_time in 
  [0-2][0-9]:[0-5][0-9]:[0-5][0-9])
     echo "correct"
esac

correctTimeFlag() {
  case $1 in
    [0-2][0-9]:[0-5][0-9]:[0-5][0-9]) return 0
  esac
  return 1
}

if correctTimeFlag "$v_time"; then
  echo "\$v_time is correct"
fi

check_time () {
[[ $(echo $v_time|awk '{for(i=1;i<=NF;i++) if( $i ~ /[0-2][0-9]:[0-5][0-9]:[0-5][0-9]/){print i}}') ]] && echo "correct" || echo "0"
}

function get_time () {
echo $v_time | awk '{for(i=1;i<=NF;i++) if( $i ~ /[0-2][0-9]:[0-5][0-9]:[0-5][0-9]/){print i}}'
}
v_time="12:12:12"

correctTimeFlag=$(get_time)