input text:
hello 34 others 28
I would like to run grep and get output the matched fields only:
34 28
I try below command but not as expected:
echo "hello 34 others 28" |grep -Eo "([0-9]+).*([0-9]+)"
You could pipe the following:
echo "hello 34 others 28" | grep -Eo '[0-9]+' | tr '\n' ' '
The matching numbers are then translated from new-line delimited values to a space separated result.
Returns: 34 28
You can add a positive lookbehind to tighten the matching criteria. You will have to use Perl mode instead of Extended mode. The lookbehind needs to be a fixed-width, so only a word character—follow by a space—is checked.
echo "hello 34 others 28" | grep -Po '(?<=\w )[0-9]+' | tr '\n' ' '