Metacharacters

Note that repeating items can also use the forms

\{n\} for exactly n items; and

\{n,\} for at least n items.

Ranges must be in ascending collating sequence. That is [a-z] and [0-9] are valid but [9-0] is not. Note that you may have to set the correct locale. We will use LOCALE=C for our collating sequence.