After  word  splitting,  unless the -f option has been set, bash scans each word for the characters *, ?, and [.  If one of these characters appears,
       then the word is regarded as a pattern, and replaced with an alphabetically sorted list of file names matching the  pattern.   If  no  matching  file
       names  are found, and the shell option nullglob is not enabled, the word is left unchanged.  If the nullglob option is set, and no matches are found,
       the word is removed.  If the failglob shell option is set, and no matches are found, an error message is printed and the command is not executed.  If
       the shell option nocaseglob is enabled, the match is performed without regard to the case of alphabetic characters.  When a pattern is used for path-
       name expansion, the character ``.''  at the start of a name or immediately following a slash must be matched explicitly, unless the shell option dot-
       glob  is  set.  When matching a pathname, the slash character must always be matched explicitly.  In other cases, the ``.''  character is not treated
       specially.  See the description of shopt below under SHELL BUILTIN COMMANDS for a description of the  nocaseglob,  nullglob,  failglob,  and  dotglob
       shell options.

       The  GLOBIGNORE  shell variable may be used to restrict the set of file names matching a pattern.  If GLOBIGNORE is set, each matching file name that
       also matches one of the patterns in GLOBIGNORE is removed from the list of matches.  The file names ``.''  and ``..''  are always ignored  when  GLO-
       BIGNORE  is set and not null.  However, setting GLOBIGNORE to a non-null value has the effect of enabling the dotglob shell option, so all other file
       names beginning with a ``.''  will match.  To get the old behavior of ignoring file names beginning with a ``.'', make ``.*''  one of the patterns in
       GLOBIGNORE.  The dotglob option is disabled when GLOBIGNORE is unset.

       Pattern Matching

       Any  character that appears in a pattern, other than the special pattern characters described below, matches itself.  The NUL character may not occur
       in a pattern.  A backslash escapes the following character; the escaping backslash is discarded when matching.  The special pattern  characters  must
       be quoted if they are to be matched literally.

       The special pattern characters have the following meanings:

       *      Matches  any string, including the null string.  When the globstar shell option is enabled, and * is used in a pathname expansion context, two
              adjacent *s used as a single pattern will match all files and zero or more directories and subdirectories.  If followed by a /,  two  adjacent
              *s will match only directories and subdirectories.
       ?      Matches any single character.
       [...]  Matches  any  one of the enclosed characters.  A pair of characters separated by a hyphen denotes a range expression; any character that sorts
              between those two characters, inclusive, using the current locale's collating sequence and character set, is matched.  If the first  character
              following the [ is a !  or a ^ then any character not enclosed is matched.  The sorting order of characters in range expressions is determined
              by the current locale and the value of the LC_COLLATE shell variable, if set.  A - may be matched by including it as the first or last charac-
              ter in the set.  A ] may be matched by including it as the first character in the set.

              Within  [  and  ],  character  classes can be specified using the syntax [:class:], where class is one of the following classes defined in the
              POSIX standard:
              alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit
              A character class matches any character belonging to that class.  The word character class matches letters, digits, and the character _.

              Within [ and ], an equivalence class can be specified using the syntax [=c=], which matches all characters with the same collation weight  (as
              defined by the current locale) as the character c.

              Within [ and ], the syntax [.symbol.] matches the collating symbol symbol.

       If  the  extglob  shell  option  is  enabled  using  the shopt builtin, several extended pattern matching operators are recognized.  In the following
       description, a pattern-list is a list of one or more patterns separated by a |.  Composite patterns may be formed using one or more of the  following
       sub-patterns:

              ?(pattern-list)
                     Matches zero or one occurrence of the given patterns
              *(pattern-list)
                     Matches zero or more occurrences of the given patterns
              +(pattern-list)
                     Matches one or more occurrences of the given patterns
              @(pattern-list)
                     Matches one of the given patterns
              !(pattern-list)
                     Matches anything except one of the given patterns