Shell-neutral expression primitive characters

^ matches only the beginning of the line

$ matches end of line only

* A single character immediately after the *, matching 0 or more of this single characters, it can also be a sequence. You can use-to represent a range of character sequences within []

\ is used to mask the special meaning of a meta-character

. Match any single character

Pattern\{n\} is used to match the number of occurrences of the preceding pattern (seemingly not less than the number of times in the shell)

Pattern\{n,\}

Pattern\{n,m\}

Shell-neutral expression primitive characters