Examples:

AB-CDR-20190201013000-1-0025B516891F-125464.csv

BC-CDR-20190201013000-2-0025B516891C-125465.csv

BC-CDR-20180201013000-3-0025B5168912-12546.csv
Pattern Description
AB Will filter the file names that have 'AB' symbols
CDR Will match all 3 files
2019 Will match the first two files which contain '2019' in their names
516891[A-Z] Will match the first two files with matches 516891F, 516891C
516891[F2] Will match the first and the third files with matches 516891F, 5168912
516891[F2]-\d{6} Will match only the first one

Some of special characters:

Quantifiers:* + ? and {}

Quantifier Description
abc* Matches a string that has ab followed by zero or more c
abc+ Matches a string that has ab followed by one or more c
abc? Matches a string that has ab followed by zero or one c
abc{2} Matches a string that has ab followed by 2 c
abc{2,} Matches a string that has ab followed by 2 or more c
abc{2,5} Matches a string that has ab followed by 2 up to 5 c
a(bc)* Matches a string that has a followed by zero or more copies of the sequence bc
a(bc){2,5} Matches a string that has a followed by 2 up to 5 copies of the sequence bc

OR operator:| or []

Operator Description
a(b|c) Matches a string that has a followed by b or c
a[bc] Same as previous

Character classes:

Class Description
\d Matches a single character that is a digit
\w Matches a word character (alphanumeric character plus underscore)
\s Matches a whitespace character (includes tabs and line breaks)
. Matches any character