$ echo "104_Fri" | sed 's/^\([0-9]+\)_\([A-Za-z]+\)$/\1;\2/' 104_Fri
I would like to match the digits at the beginning and the letters at the end - each as a group. Afterwards I want to output the first group, a semicolon and then the second group.
I would expect this expression to yield:
Why does this not work?