How to set the number of characters in a regular expression in sed?

Question

linux

This code works:

echo -e "123\n45\n678" | sed -r -e 's/([0-9]+)/замена/g'

But as soon as I specify the number of characters, the code does not work:

echo -e "123\n45\n678" | sed -r -e 's/([0-9](2-3))/замена/g'

I need to search for complex strings by a specific mask, while some strings may differ from each other in the mask by just the number of digits following each other. To do this, I need to specify the expected number of characters in the sed regular expression.

Answer 1

sed -r -e 's/([0-9] {2,3} )/replace/g'