Share to: share facebook share twitter share wa share telegram print page

Glob (programming)

In computer programming, glob (/ɡlɒb/) patterns specify sets of filenames with wildcard characters. For example, the Unix Bash shell command mv *.txt textfiles/ moves all files with names ending in .txt from the current directory to the directory textfiles. Here, * is a wildcard and *.txt is a glob pattern. The wildcard * stands for "any string of any length including empty, but excluding the path separator characters (/ in unix and \ in windows)".

The other common wildcard is the question mark (?), which stands for one character. For example, mv ?.txt shorttextfiles/ will move all files named with a single character followed by .txt from the current directory to directory shorttextfiles, while ??.txt would match all files whose name consists of 2 characters followed by .txt.

In addition to matching filenames, globs are also used widely for matching arbitrary strings (wildcard matching). In this capacity a common interface is fnmatch.

Origin

A screenshot of the original 1971 Unix reference page for glob – the owner is dmr, short for Dennis Ritchie.

The glob command, short for global, originates in the earliest versions of Bell Labs' Unix.[1] The command interpreters of the early versions of Unix (1st through 6th Editions, 1969–1975) 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.

Glob was originally written in the B programming language. It was the first piece of mainline Unix software to be developed in a high-level programming language.[2] Later, this functionality was provided as a C library function, glob(), used by programs such as the shell. It is usually defined based on a function named fnmatch(), which tests for whether a string matches a given pattern - the program using this function can then iterate through a series of strings (usually filenames) to determine which ones match. Both functions are a part of POSIX: the functions defined in POSIX.1 since 2001, and the syntax defined in POSIX.2.[3][4] The idea of defining a separate match function started with wildmat (wildcard match), a simple library to match strings against Bourne Shell globs.

Traditionally, globs do not match hidden files in the form of Unix dotfiles; to match them the pattern must explicitly start with .. For example, * matches all visible files while .* matches all hidden files.

Syntax

The most common wildcards are *, ?, and […].

Wildcard Description Example Matches Does not match
* matches any number of any characters including none Law* Law, Laws, or Lawyer GrokLaw, La, or aw
*Law* Law, GrokLaw, or Lawyer. La, or aw
? matches any single character ?at Cat, cat, Bat or bat at
[abc] matches one character given in the bracket [CB]at Cat or Bat cat, bat or CBat
[a-z] matches one character from the (locale-dependent) range given in the bracket Letter[0-9] Letter0, Letter1, Letter2 up to Letter9 Letters, Letter or Letter10

Normally, the path separator character (/ on Linux/Unix, MacOS, etc. or \ on Windows) will never be matched. Some shells, such as Bash have functionality allowing users to circumvent this.[5]

Unix-like

On Unix-like systems *, ? is defined as above while […] has two additional meanings:[6][7]

Wildcard Description Example Matches Does not match
[!abc] matches one character that is not given in the bracket [!C]at Bat, bat, or cat Cat
[!a-z] matches one character that is not from the range given in the bracket Letter[!3-5] Letter1, Letter2, Letter6 up to Letter9 and Letterx etc. Letter3, Letter4, Letter5 or Letterxx

The ranges are also allowed to include pre-defined character classes, equivalence classes for accented characters, and collation symbols for hard-to-type characters. They are defined to match up with the brackets in POSIX regular expressions.[6][7]

Unix globbing is handled by the shell per POSIX tradition. Globbing is provided on filenames at the command line and in shell scripts.[8] The POSIX-mandated case statement in shells provides pattern-matching using glob patterns.

Some shells (such as the C shell and Bash) support additional syntax known as alternation or brace expansion. Because it is not part of the glob syntax, it is not provided in case. It is only expanded on the command line before globbing.

The Bash shell also supports the following extensions:[9]

  • Extended globbing (extglob): allows other pattern matching operators to be used to match multiple occurrences of a pattern enclosed in parentheses, essentially providing the missing kleene star and alternation for describing regular languages. It can be enabled by setting the extglob shell option. This option came from ksh93.[10] The GNU fnmatch and glob has an identical extension.[3]
  • globstar: allows ** on its own as a name component to recursively match any number of layers of non-hidden directories.[10] Also supported by the JS libraries and Python's glob.

Windows and DOS

The dir command with a glob pattern in IBM PC DOS 1.0.

The original DOS was a clone of CP/M designed to work on Intel's 8088 and 8086 processors. Windows shells, following DOS, do not traditionally perform any glob expansion in arguments passed to external programs. Shells may use an expansion for their own builtin commands:

  • Windows PowerShell has all the common syntax defined as stated above without any additions.[11]
  • COMMAND.COM and cmd.exe have most of the common syntax with some limitations: There is no […] and for COMMAND.COM the * may only appear at the end of the pattern. It can not appear in the middle of a pattern, except immediately preceding the filename extension separator dot.

Windows and DOS programs receive a long command-line string instead of argv-style parameters, and it is their responsibility to perform any splitting, quoting, or glob expansion. There is technically no fixed way of describing wildcards in programs since they are free to do what they wish. Two common glob expanders include:[12]

  • The Microsoft C Runtime (msvcrt) command-line expander, which only supports ? and *.[13] Both ReactOS (crt/misc/getargs.c) and Wine (msvcrt/data.c) contain a compatible open-source implementation of __getmainargs, the function operating under-the-hood, in their core CRT.
  • The Cygwin and MSYS dcrt0.cc command-line expander, which uses the unix-style glob() routine under-the-hood, after splitting the arguments.

Most other parts of Windows, including the Indexing Service, use the MS-DOS style of wildcards found in CMD. A relic of the 8.3 filename age, this syntax pays special attention to dots in the pattern and the text (filename). Internally this is done using three extra wildcard characters, <>". On the Windows API end, the glob() equivalent is FindFirstFile, and fnmatch() corresponds to its underlying RtlIsNameInExpression.[14] (Another fnmatch analogue is PathMatchSpec.) Both open-source msvcrt expanders use FindFirstFile, so 8.3 filename quirks will also apply in them.

SQL

The SQL LIKE operator has an equivalent to ? and * but not […].

Common wildcard SQL wildcard Description
? _ matches any single character
* % matches any number of any characters including none

Standard SQL uses a glob-like syntax for simple string matching in its LIKE operator, although the term "glob" is not generally used in the SQL community. The percent sign (%) matches zero or more characters and the underscore (_) matches exactly one.

Many implementations of SQL have extended the LIKE operator to allow a richer pattern-matching language, incorporating character ranges ([…]), their negation, and elements of regular expressions.[15]

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.[16]

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, depending on implementation details, regular expressions may match a substring.

Implementing as regular expressions

The original Mozilla proxy auto-config implementation, which provides a glob-matching function on strings, uses a replace-as-RegExp implementation as above. The bracket syntax happens to be covered by regex in such an example.

Python's fnmatch uses a more elaborate procedure to transform the pattern into a regular expression.[17]

Other implementations

Beyond their uses in shells, globs patterns also find use in a variety of programming languages, mainly to process human input. A glob-style interface for returning files or an fnmatch-style interface for matching strings are found in the following programming languages:

  • C# has multiple libraries available through NuGet such as Glob.[18] or DotNet.Glob.[19]
  • D has a globMatch function in the std.path module.[20]
  • JavaScript has a library called minimatch which is used internally by npm, and micromatch, a purportedly more optimized, accurate and safer globbing implementation used by Babel and yarn.[21][22]
  • Go has a Glob function in the filepath package.[23]
  • Java has a Files class containing methods that operate on glob patterns.[24]
  • Haskell has a Glob package 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.[25]
  • Perl has both a glob function (as discussed in Larry Wall's book Programming Perl) and a Glob extension which mimics the BSD glob routine.[26] Perl's angle brackets can be used to glob as well: <*.log>.
  • PHP has a glob function.[27]
  • Python has a glob module in the standard library which performs wildcard pattern matching on filenames,[28] and an fnmatch module with functions for matching strings or filtering lists based on these same wildcard patterns.[17] Guido van Rossum, author of the Python programming language, wrote and contributed a glob routine to BSD Unix in 1986.[29] There were previous implementations of glob, e.g., in the ex and ftp programs in previous releases of BSD.
  • Ruby has a glob method for the Dir class which performs wildcard pattern matching on filenames.[30] Several libraries such as Rant and Rake provide a FileList class which has a glob method or use the method FileList.[] identically.
  • Rust has multiple libraries that can match glob patterns.[31]
  • SQLite has a GLOB function.
  • Tcl contains a globbing facility.[32]

See also

References

  1. ^ "First Edition Unix manual 'Miscellaneous' section (PDF)" (PDF). Archived from the original (PDF) on 2000-08-29. Retrieved 2011-05-11.
  2. ^ McIlroy, M. D. (1987). A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 (PDF) (Technical report). CSTR. Bell Labs. 139.
  3. ^ a b fnmatch(3) – Linux Programmer's Manual – Library Functions
  4. ^ glob(3) – Linux Programmer's Manual – Library Functions
  5. ^ https://www.gnu.org/software/bash/manual/bash.html#Pattern-Matching Archived 2018-03-15 at the Wayback Machine Bash Reference Manual
  6. ^ a b "The Open Group Base Specifications Issue 7 IEEE Std 1003.1, 2013 Edition, 2.13. Pattern Matching Notation". Archived from the original on 2014-04-27. Retrieved 2015-10-26.
  7. ^ a b "Linux Programmer's Manual, GLOB(7)". Archived from the original on 2015-10-31. Retrieved 2015-10-26.
  8. ^ The "Advanced Bash-Scripting Guide, Chapter 19.2: Globbing" (Mendel Cooper, 2003) has a concise set of examples of filename globbing patterns.
  9. ^ "Bash globs". greg's bash knowledgebase. Archived from the original on 2019-11-18. Retrieved 2019-11-25.
  10. ^ a b "Pattern Matching". Bash Reference Manual. Archived from the original on 2016-02-11. Retrieved 2016-01-11.
  11. ^ "Supporting Wildcard Characters in Cmdlet Parameters". Microsoft. Microsoft Developer Network.
  12. ^ "Wildcard Expansion". Microsoft Developer Network. 2013. Archived from the original on 2014-08-22. Retrieved 2013-10-16.
  13. ^ "Wildcard Expansion". docs.microsoft.com. 2022-02-08.
  14. ^ Wildcards in Windows Archived 2019-12-24 at the Wayback Machine. MSDN Devblog.
  15. ^ "LIKE (Transact-SQL)". 2023-05-23. Archived from the original on 2017-08-02. Retrieved 2017-08-01.
  16. ^ Hopcroft, John E.; Motwani, Rajeev; Ullman, Jeffrey D. (2000). Introduction to Automata Theory, Languages, and Computation (2nd ed.). Addison-Wesley.
  17. ^ a b "Lib/fnmatch.py". Python. 2021-01-20. Archived from the original on 2021-11-10. Retrieved 2021-11-10.
  18. ^ "kthompson/glob". GitHub. Archived from the original on 2020-10-26. Retrieved 2020-11-06.
  19. ^ "dazinator/dotnet.glob". GitHub. Archived from the original on 2022-06-22. Retrieved 2022-06-22.
  20. ^ "std.path - D Programming Language - Digital Mars". dlang.org. Archived from the original on 2014-09-08. Retrieved 2014-09-08.
  21. ^ "isaacs/minimatch". GitHub. Archived from the original on 2016-07-28. Retrieved 2016-08-10.
  22. ^ "jonschlinkert/micromatch". GitHub. Archived from the original on 2016-02-11. Retrieved 2017-04-04.
  23. ^ "Package filepath - The Go Programming Language". Golang.org. Archived from the original on 2011-05-25. Retrieved 2011-05-11.
  24. ^ "File Operations". Oracle. Archived from the original on 2013-09-20. Retrieved 2013-12-16.
  25. ^ "Glob-0.7.4: Globbing library". Archived from the original on 2014-05-08. Retrieved 2014-05-07.
  26. ^ "File::Glob - Perl extension for BSD glob routine". perldoc.perl.org. Retrieved 2011-05-11.
  27. ^ "glob - Manual". PHP. 2011-05-06. Archived from the original on 2017-11-13. Retrieved 2011-05-11.
  28. ^ "10.7. glob — Unix style pathname pattern expansion — Python v2.7.1 documentation". Docs.python.org. Archived from the original on 2011-05-16. Retrieved 2011-05-11.
  29. ^ "'Globbing' library routine". Archived from the original on 2007-12-19. Retrieved 2011-05-11.
  30. ^ "Class: Dir". Ruby-doc.org. Archived from the original on 2011-05-15. Retrieved 2011-05-11.
  31. ^ "#glob - Lib.rs". lib.rs. Archived from the original on 2021-11-12. Retrieved 2021-11-12.
  32. ^ "TCL glob manual page". Archived from the original on 2011-12-08. Retrieved 2011-11-16.

Read other articles:

佐賀大学教育学部附属小学校 北緯33度14分43.4秒 東経130度18分14.4秒 / 北緯33.245389度 東経130.304000度 / 33.245389; 130.304000座標: 北緯33度14分43.4秒 東経130度18分14.4秒 / 北緯33.245389度 東経130.304000度 / 33.245389; 130.304000過去の名称 佐賀県尋常師範学校附属小学校佐賀県師範学校附属小学校佐賀県師範学校附属国民学校佐賀師範学校男子部附属国民学校…

Astan-e Quds-e Razavi Astan Quds RazaviNative nameآستان قدس رضویTypeBonyadFoundedApril 11, 1510; 513 years ago (1510-04-11)FounderIsmail IHeadquartersMashhad, Khorasan Razavi, IranKey peopleAhmad Marvi (Custodian and Chairman of the supervisory board)TBA (President and CEO)WebsiteOfficial website Astan Quds Razavi (Persian: آستان قدس رضوی, romanized: Āstān-e Qods-e Razavi) is a bonyad based at Mashhad, Iran. It is the administrative organization w…

瑠璃寺 本堂所在地 兵庫県佐用郡佐用町船越877位置 北緯35度6分12.3秒 東経134度25分25.6秒 / 北緯35.103417度 東経134.423778度 / 35.103417; 134.423778座標: 北緯35度6分12.3秒 東経134度25分25.6秒 / 北緯35.103417度 東経134.423778度 / 35.103417; 134.423778山号 船越山宗旨 古義真言宗宗派 高野山真言宗寺格 別格本山本尊 千手観世音菩薩創建年 伝・神亀5年(728年)開…

Салат «Олів'є» Тип салатПоходження Російська імперіяАвтор Люсьєн Олів'є  Медіафайли у Вікісховищі Салат Олів'є — популярний в країнах колишнього СРСР салат, який вважається святковим і традиційним новорічним[1]. Назву дістав на честь свого творця, шеф-кухаря Люс

This article uses bare URLs, which are uninformative and vulnerable to link rot. Please consider converting them to full citations to ensure the article remains verifiable and maintains a consistent citation style. Several templates and tools are available to assist in formatting, such as reFill (documentation) and Citation bot (documentation). (August 2022) (Learn how and when to remove this template message) Grace Presbyterian Church of New ZealandClassificationProtestantOrientationconservativ…

Athletics at the1990 Commonwealth GamesTrack events100 mmenwomen200 mmenwomen400 mmenwomen800 mmenwomen1500 mmenwomen3000 mwomen5000 mmen10,000 mmenwomen100 m hurdleswomen110 m hurdlesmen400 m hurdlesmenwomen3000 msteeplechasemen4×100 m relaymenwomen4×400 m relaymenwomenRoad eventsMarathonmenwomen10 km walkwomen30 km walkmenField eventsHigh jumpmenwomenPole vaultmenLong jumpmenwomenTriple jumpmenShot putmenwomenDiscus throwmenwomenHammer throwmenJavelin throwmenwomenCombined eventsHeptathlonwo…

2016 film by Mike Flanagan HushPromotional posterDirected byMike FlanaganWritten by Mike Flanagan Kate Siegel Produced by Trevor Macy Jason Blum Starring John Gallagher Jr. Michael Trucco Kate Siegel CinematographyJames KniestEdited byMike FlanaganMusic byThe Newton BrothersProductioncompanies Blumhouse Productions Intrepid Pictures Distributed byNetflixRelease dates March 12, 2016 (2016-03-12) (SXSW) April 8, 2016 (2016-04-08) (United States) Running time81…

American baseball player (born 1988) Baseball player Ben RevereRevere with the Washington Nationals in 2016OutfielderBorn: (1988-05-03) May 3, 1988 (age 35)Atlanta, Georgia, U.S.Batted: LeftThrew: RightMLB debutSeptember 7, 2010, for the Minnesota TwinsLast MLB appearanceOctober 1, 2017, for the Los Angeles AngelsMLB statisticsBatting average.284Home runs7Runs batted in198Stolen bases211 Teams Minnesota Twins (2010–2012) Philadelphia Phillies (2013–2015) To…

2018 Indian TV Series For the 2001 film of the same name, see Minnale (film). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Minnale TV series – news · newspapers · books · scholar · JSTOR (May 2019) (Learn how and when to remove this template message) MinnaleGenreSoap operaWritten byRadaan Mediaworks Dia…

Island Pelican, you are invited to the Teahouse! Hi Island Pelican! Thanks for contributing to Wikipedia. Be our guest at the Teahouse! The Teahouse is a friendly space where new editors can ask questions about contributing to Wikipedia and get help from experienced editors like Nick Moyes (talk). Visit the Teahouse We hope to see you there! Delivered by HostBot on behalf of the Teahouse hosts 16:01, 27 November 2021 (UTC) Your edits on Sexual Objectification Greetings. I rolled back your edits …

1994 studio album by Jello Biafra & Mojo NixonPrairie Home InvasionStudio album by Jello Biafra & Mojo NixonReleasedMarch 24, 1994Recorded1994GenreCowpunk[1][2]Length62:00LabelAlternative TentaclesProducerMarshall LawlessJello Biafra chronology Tumor Circus(1991) Prairie Home Invasion(1994) Beyond the Valley of the Gift Police(1994) Mojo Nixon chronology Horny Holidays!(1992) Prairie Home Invasion(1994) Live in Las Vegas (Pleasure Barons)(1994) Prairie Home Invasi…

Pour les autres membres de la famille, voir Maison de La Trémoille. Charles Belgique Hollande de La TrémoilleTitre de noblesseVicomteBiographieNaissance 1655La HayeDécès 1er juin 1709ParisActivité FeudataireFamille Maison de La TrémoillePère Henri Charles de La TrémoilleMère Emilie von Hessen-Kassel (d)Conjoint Madeleine de Créquy (d)Enfants Marie Armande de La TrémoilleCharles Louis Bretagne de La TrémoïlleAutres informationsDistinctions Chevalier de l'ordre du Saint-EspritChevalie…

2005 video gameKey of HeavenDeveloper(s)Climax EntertainmentPublisher(s)Sony Computer EntertainmentPlatform(s)PlayStation PortableReleaseJP: July 21, 2005NA: November 15, 2005EU: March 24, 2006AU: March 30, 2006Genre(s)Action role-playingMode(s)Single-player Kingdom of Paradise is an action role-playing video game available for the PlayStation Portable handheld system. The game is called Tenchi no Mon (天地の門) in Japan and Key of Heaven in Europe. On April 24, 2008 it was released as a dow…

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Muradid dynasty – news · newspapers · books · scholar · JSTOR (June 2022) (Learn how and when to remove this template message)Muradid dynastyCountryOttoman TunisiaFounded1613FounderMurad IFinal rulerMurad IIITitlesBeyDeposition1702 The Muradid dynasty was a dynast…

Webcomic by Kate Ashwin WiddershinsCover of Widdershins Volume 9Author(s)Kate Ashwin Widdershins is a webcomic by Kate Ashwin.[1] Synopsis Widdershins is set in the magical city of the same name in Yorkshire, England, during the Industrial Revolution. While machines are replacing magic as the main tool of work in many other English cities, technology is banned in the city of Widdershins.[1][2] The story begins with wizard and stage magician Sidney Malik, who accidentally …

Indian TV series or programme Veer ShivajiGenreHistorical dramaCreated byAbhimanyu SinghWritten byStoryRajesh SakshamScreenplayFaizal AkhtarVirendra Singh PatyalDialoguesMairaj Zaidi StarringParas AroraShilpa TulaskarPalak JainAyesha KaduskarHemant Choudhary Ahmad HarhashComposersSunny BawraInder BawraCountry of originIndiaOriginal languageHindiNo. of seasons1No. of episodes182ProductionProducerAbhimanyu SinghCinematographyVeerdhaval PuranikEditorsRochak AhujaAyaz Ahmad Shadab (online)Camer…

Type of Japanese pottery This article uses bare URLs, which are uninformative and vulnerable to link rot. Please consider converting them to full citations to ensure the article remains verifiable and maintains a consistent citation style. Several templates and tools are available to assist in formatting, such as reFill (documentation) and Citation bot (documentation). (August 2022) (Learn how and when to remove this template message) Natural glaze ware jar, excavated at Ise, Mie, Heian period, …

Israeli reality television competition This article is about reality singing competition. For other uses, see Voice of Israel (disambiguation). The Voice IsraelHebrewThe Voice ישראל Created byJohn de MolRoel van VelzenPresented by Michael Aloni Shlomit Malka Judges Rami Kleinstein Sarit Hadad Aviv Geffen Shlomi Shabat Yuval Banai & Shlomi Bracha Mosh Ben-Ari Miri Mesika Avraham Tal Ivri Lider Nasrin Kadri Doron Medalie Shlomi Shabat & Yuval Dayan Country of originIsraelOriginal lang…

Specific land area in which radio transmissions are heavily restricted 38°22′30″N 79°30′00″W / 38.375°N 79.5°W / 38.375; -79.5 The NRQZ includes portions of West Virginia, Virginia, and a small part of Maryland. The National Radio Quiet Zone (NRQZ) is a large area of land in the United States designated as a radio quiet zone, in which radio transmissions are restricted by law to facilitate scientific research and the gathering of military intelligence. About h…

This article consists almost entirely of a plot summary. Please help improve the article by adding more real-world context. (March 2021) (Learn how and when to remove this template message) 2016 Indian filmMotu Patlu King of KingsTheatrical Release PosterDirected bySuhas D. KadavBased onMotu Patluby Kripa Shankar BhardwajProduced byKetan MehtaMusic byVishal Bhardwaj[1]ProductioncompaniesViacom 18 Motion PicturesCosmos-MayaDistributed byViacom 18 Motion PicturesRelease date 14 Octobe…

Kembali kehalaman sebelumnya

Lokasi Pengunjung: 3.147.195.163