Add lines if they are missing from a data series

Question

I have a data gathering device which records 5 attributes of data per second. The first column of the data is the time elapsed, in seconds, and is always sequential ie n+1. Data fields are comma delimited.

Randomly, the device doesn't record a sample and thus in the file there a skip of a second, and sometimes more. For example below sample number 167 is missing

166,1.09424,240,76,132
168,1.10088,215,76,132
169,1.10765,213,78,131
170,1.11458,198,79,131

and in this one, 294 and 295 are missing

292,2.04078,285,66,108
293,2.04673,302,64,108
296,2.06309,306,67,109
297,2.06859,370,66,109

The collected data will have an arbitrary number of lines/samples up to 1 million of more data points in a session. The number of dropped samples could be over 200, scattered randomly throughout.

I'm looking for a script or command that runs through the file and if a line is missing, will add a new line, and add the time stamp/sample number like this

166,1.09424,240,76,132
167
168,1.10088,215,76,132
169,1.10765,213,78,131
170,1.11458,198,79,131

or this

292,2.04078,285,66,108
293,2.04673,302,64,108
294
295
296,2.06309,306,67,109
297,2.06859,370,66,109

I found this answer which is a partial answer but gives lots of wrong new lines. I asked this question in a less precise form and got a better answer but it still didn't get me the solution.

Would prefer BASH script, using commands that run on OSX 10.14.2. Thanks in advance.

Answer 1

This might be a one-liner for you

awk -F, 'n==""||n>$1{n=$1}{while(n!=$1){print n++}}{print;n++}' < input > output

though it's not much different to what you had before, except the "protection" for the case when the number series suddenly warps to a lower number.