Linux file get lines with column matching specific datetime range

Question

How to get lines matching datetime range. For example, get all lines between 2017-09-08 00:00:00 and 2017-09-09 00:00:00. Delimiter is space.

file:

2017-09-07 19:00:01 a
2017-09-08 20:00:01 a
2017-09-08 21:00:03 a
2017-09-10 19:00:01 a

output:

2017-09-08 20:00:01 a
2017-09-08 21:00:03 a

Answer 1

awk '$1FS$2> "2017-09-08 00:00:00"  && $1FS$2 <"2017-09-09 00:00:00"' inputfile
2017-09-08 20:00:01 a
2017-09-08 21:00:03 a

Or you can store the times in variables:

awk -v start="2017-09-08 00:00:00" -v end="2017-09-09 00:00:00" '$1FS$2> start  && $1FS$2 <end' inputfile
2017-09-08 20:00:01 a
2017-09-08 21:00:03 a

Explanation:

$1 means the first column $2 means the second column FS means field separator, which is by default is space. $1FS$2 means first two columns together as one entity. This was needed because there is space between your date and time column.