I am looking to take a string as command parameter like `HHMMSS` and convert it to time format like `HH:MM:SS` and append it to current date (date needs to be generated within the script using 'date' command )

For example, if my command line argument will be `093500`, this should be converted to `09:35:00` and be appended with current date like,
`2018-05-16 09:35:00` 

Example:

```
$ ./convertTime.sh 093500
2018-05-16 09:35:00

```