Most metacharacters lose their special meaning inside lists. The period .B . matches any single character. The preceding item is optional and matched at most once. The preceding item will be matched zero or more times. The preceding item is matched exactly .I n times.
Repetition takes precedence over concatenation, which in turn takes precedence over alternation.
A whole subexpression may be enclosed in parentheses to override these precedence rules. This variable specifies default options to be placed in front of any explicit options. Option specifications are separated by whitespace. A backslash escapes the next character, so it can be used to specify an option containing whitespace or a backslash. The locale is determined by the first of these variables that is set.