### pdbzerofill - fills a columns with zeros (or other value) when blank

`pdbzerofill` fills a row that is missing in a series of rows with a
numerical increasing (frequently a timestamp) index This is a sister
program to `pdbensure` which removes rows with missing data instead of
creating them.

#### Example input (*myblanks.fsdb*):

```
#fsdb -F t col1:l two:a andthree:d
2	key1	42.0
6	key2	
10	    90.2
```

#### Example command usage

```
$ pdbzerofill -c two andthree -v xxx -b 2 -t col1
```

#### Example output

```
#fsdb -F t col1:l two andthree:d
2	key1	42.0
4	xxx	xxx
6	key2	
8	xxx	xxx
10		90.2
```