In computer programming, in particular in a Unix-like environment, glob patterns specify sets of filenames with wildcard characters. For example, the Unix command
mv *.txt textfiles/ moves (
mv) all files with names ending in
.txt from the current directory to the directory
* is a wildcard standing for "any string of characters" and
*.txt is a glob pattern. The other common wildcard is the question mark (
?), which stands for one character.
The command interpreters of the early versions of Unix (1st through 6th Editions, 1969–75) relied on a separate program to expand wildcard characters in unquoted arguments to a command: /etc/glob. That program performed the expansion and supplied the expanded list of file paths to the command for execution. Its name is an abbreviation for "global command". Later, this functionality was provided as a library function, glob(), used by programs such as the shell.
The most common wildcards are
|Wildcard||Description||Example||Matches||Does not match|
||matches any number of any characters including none||
||matches any single character||
||matches one character given in the bracket||
||matches one character from the range given in the bracket||
In all cases the path separator character (
/ on Unix or
\ on Windows) will never be matched.
|Wildcard||Description||Example||Matches||Does not match|
||matches one character that is not given in the bracket||
||matches one character that is not from the range given in the bracket||
The Bash shell also supports Extended Globbing which allows other pattern matching operators to be used to match multiple occurrences of a pattern enclosed in parentheses. It can be enabled by setting the
extglob shell option.
DOS COMMAND.COM and Windows cmd.exe
The SQL LIKE operator has an equivalent of
*. There is no equivalent of
|Common wildcard||SQL wildcard|
Standard SQL uses a glob-like syntax for simple string matching in its
LIKE operator. The percent sign (%) matches zero or more characters, and the underscore matches exactly one character. The term "glob" is not generally used in the SQL community, however. Many implementations of SQL have extended the
LIKE operator to allow a richer pattern-matching language incorporating elements of regular expressions.
Compared to regular expressions
Globs do not include syntax for the Kleene star which allows multiple repetitions of the preceding part of the expression; thus they are not considered regular expressions, which can describe the full set of regular languages over any given finite alphabet.
|Common wildcard||Equivalent regular expression|
Globs attempt to match the entire string (for example,
S*.DOC matches S.DOC and SA.DOC, but not POST.DOC or SURREY.DOCKS), whereas regular expressions match a substring unless the expression is enclosed with
$ (so the equivalent of
The term "glob" is also used to refer more generally to limited pattern-matching facilities of this kind, in other contexts:
- D has a
globMatchfunction in the
- NodeJS has a library called
minimatchwhich is used internally by npm, and
micromatch, a purportedly more optimized, accurate and safer globbing implementation.
- Go has a
Globfunction in the
- Java has a
Filesclass containing methods that operate on glob patterns.
- Haskell has a
Globpackage with the main module
System.FilePath.Glob. The pattern syntax is based on a subset of Zsh’s. It tries to optimize the given pattern and should be noticeably faster than a naïve character-by-character matcher.
- Perl has both a
globfunction (as discussed in Larry Wall's book Programming Perl) and a Glob extension which mimics the BSD glob routine. Perl's angle brackets can be used to glob as well:
- PHP has a
- Python has a
globmodule in the standard library which performs wildcard pattern matching on filenames, and an
fnmatchmodule with functions for matching strings or filtering lists based on these same wildcard patterns Guido van Rossum, author of the Python programming language, wrote and contributed a
globroutine to BSD Unix in 1986. There were previous implementations of
glob, e.g., in the ex and ftp programs in previous releases of BSD.
- Ruby has a
globmethod for the
Dirclass which performs wildcard pattern matching on filenames. Several libraries such as Rant and Rake provide a
FileListclass which has a glob method or use the method
- SQLite has a
- Tcl contains both true regular expression matching facilities and a more limited kind of pattern matching often described as globbing.
- "First Edition Unix manual 'Miscellaneous' section (PDF)" (PDF). Retrieved 2011-05-11.
- 1st Edition UNIX, code.google.com, src/cmd/glob.c
- "The Open Group Base Specifications Issue 7 IEEE Std 1003.1, 2013 Edition, 2.13. Pattern Matching Notation".
- "Linux Programmer's Manual, GLOB(7)".
- "Pattern Matching". Bash Reference Manual.
- "Supporting Wildcard Characters in Cmdlet Parameters".
- "LIKE (Transact-SQL)".
.does not match a newline. To match newlines, the equivalents are
[\s\S]*or similar complementary pairs, respectively.
- The "Advanced Bash-Scripting Guide, Chapter 19.2: Globbing" (Mendel Cooper, 2003) has a concise set of examples of filename globbing patterns.
- "Wildcard Expansion". Microsoft Developer Network. 2013.
- "Expanding Wildcard Arguments". Microsoft Developer Network. 2013.
- "Supporting Wildcard Characters in Cmdlet Parameters". Microsoft Developer Network. 2013.
- "std.path - D Programming Language - Digital Mars". dlang.org. Retrieved 2014-09-08.
- "isaacs/minimatch". GitHub. Retrieved 2016-08-10.
- "minimatch". npm. Retrieved 2016-08-10.
- "jonschlinkert/micromatch". GitHub. Retrieved 2017-04-04.
- "micromatch". npm. Retrieved 2017-04-04.
- "Package filepath - The Go Programming Language". Golang.org. Retrieved 2011-05-11.
- "File Operations". Oracle. Retrieved 2013-12-16.
- "Glob-0.7.4: Globbing library". Retrieved 2014-05-07.
- Contact details. "File::Glob - Perl extension for BSD glob routine". perldoc.perl.org. Retrieved 2011-05-11.
- "glob - Manual". PHP. 2011-05-06. Retrieved 2011-05-11.
- "10.7. glob — Unix style pathname pattern expansion — Python v2.7.1 documentation". Docs.python.org. Retrieved 2011-05-11.
- "10.8 fnmatch Unix filename pattern matching -- Python v2.7.7 documentation". Docs.python.org. Retrieved 2014-06-28.
- "'Globbing' library routine". Archived from the original on 2007-12-19. Retrieved 2011-05-11.
- "Class: Dir". Ruby-doc.org. Retrieved 2011-05-11.
- "TCL glob manual page". Retrieved 16 November 2011.