Regular Characters
They are literal characters that match themselves exactly in a pattern. They represent the actual character you want to find.
Examples:
amatches the literal letter “a”5matches the literal digit “5”
Meta-characters
They are special characters that have predefined meanings and functions in regular expressions. They don’t match themselves literally but instead control how the pattern matching works.
Common meta-characters include:
.- matches any single character^- matches the beginning of a line$- matches the end of a line*- matches 0 or more of the preceding character+- matches 1 or more of the preceding character?- matches 0 or 1 of the preceding character[]- defines a character set()- creates groups|- logical OR operator