Question

I am new to bash and having a tough time figuring this out.

Using sed, could anyone help me in finding only even numbers in a given file?

I figured out how to find all numbers starting from [0,2,4,6,8] using this:

sed -n 's/^[0-9]*[02468] /&/w even' <file 

But this doesn’t guarantee that the number is even for sure.

I am having trouble in finding if the matched number ends with either [0,2,4,6,8] for it to be even for sure.

So can any one help me out with this?

Answer 1

Your regex looks a bit weird and I am not sure what you want to do, but this should help:

sed -r -n 's/^[0-9]*?[02468] /even/g'

-r to enable extended regex, *? to make it non-greedy, and /g to perform replacement globally for all lines in file.