Sets and ranges example in regex

Example - find all special devices which are in form: /dev/sda, /dev/sda1, /dev/sdb2 etc:

$ egrep '/dev/[a-z]*[0-9]?' /etc/mtools.conf

Output:

drive a: file="/dev/fd0" exclusive
drive b: file="/dev/fd1" exclusive
# drive c: file="/dev/sda1"
# drive c: file="/dev/hda1"
# drive z: file="/dev/sda4"