Question

Given a filename in the form someletters_12345_moreleters.ext, I want to extract the 5 digits and put them into a variable.

So to emphasize the point, I have a filename with x number of characters then a five digit sequence surrounded by a single underscore on either side then another set of x number of characters. I want to take the 5 digit number and put that into a variable.

I am very interested in the number of different ways that this can be accomplished.

Answer 1

Use cut:

echo 'someletters_12345_moreleters.ext' | cut -d'_' -f 2 

More generic:

INPUT='someletters_12345_moreleters.ext' SUBSTRING=$(echo $INPUT| cut -d'_' -f 2) echo $SUBSTRING