Valid character classes for the [] glob are defined by the POSIX standard:. The –E flag allows regex matching, while the "/$" represents the end of the string. All the documentation I've seen says that . Just enter your string and regular expression and this utility will automatically extract all string fragments that match to the given regex. To get further numbers, consider Matches() or NextMatch. Posts: 9 Thanks Given: 0. Using BASH =~ regex to match multiple strings I have a scripting problem that I'm trying to solve, whereby I want to match that a string contains either of three strings. Use the == operator with the [ [ command for pattern matching. for extended globbing, see here and some simple examples here . All … It returns as follows: Join Date: Nov 2008. Linux bash provides a lot of commands and features for Regular Expressions or regex. Extract variables from text file into array with Bash, Perl and Regex. Lastly I hope this tutorial to search and print exact match in Linux and Unix was helpful. I need a function Page 2 of 2 < 1: 2 Thread Tools: Search this Thread : Top Forums Shell Programming and Scripting Using BASH =~ regex to match multiple strings # 8 04-28-2014 Scrutinizer. You can also check our guide about string concatenation .eval(ez_write_tag([[250,250],'linuxize_com-large-mobile-banner-1','ezslot_14',157,'0','0'])); If you have any questions or feedback, feel free to leave a comment. When this operator is used, the right string is considered as a regular expression. Using Regex Operator # Another option to determine whether a specified substring occurs within a string is to use the regex operator =~. share | improve this question | follow | asked Sep 17 '19 at 8:52. For information about the language elements used to build a regular expression pattern, see Regular Expression Language - Quick Reference. Types of string patterns can be Exact or Regular expression. For your From the source: The GNU bash manual, Conditional Constructsand Bash Variables. 1. I'm sure this is simple, I just can't get my brain around it. Using separate matches against shorter strings, or using arrays of strings instead of a single long string, may be faster. I am trying to write a bash script that contains a function so when given a .tar, .tar.bz2, .tar.gz etc. In this tutorial I showed you multiple grep examples to match exact pattern or string using regex. Match everything except for specified strings . 203 1 1 gold badge 2 2 silver badges 9 9 bronze badges. Moderator. Linux bash provides a lot of commands and features for Regular Expressions or regex. Quick Reference. Despite only BRE being supported grouping works also. Digits: We extract a group of digit characters and access the Value string representation of that number. Use the = operator with the test [ command. Now since "prasad" is the last word in my name is deepak prasad hence the bash pattern match is successful. Last Activity: 1 January 2021, 1:47 AM EST. Does anyone know a bash command to check for a pattern match within a string. pat='[^0-9]+([0-9]+)'s='I am a string with some digits 1024'[[ $s =~ $pat ]] # $pat must be unquotedecho "${BASH_REMATCH[0]}"echo "${BASH_REMATCH[1]}" Output: I am a string with some digits 10241024. Load a string, get regex matches. ... slower in cases that involve complex back-tracking (usually that means extglob quantifier nesting). Donate. share | improve this question | follow | asked Sep 17 '19 at 8:52. Ensure not to quote the regular expression. Online regex tester, debugger with highlighting for PHP, PCRE, Python, Golang and JavaScript. 2. Conclusion. The exact command may differ based on your requirement, these were some of the common use cases where you can grep exact match with some basic regex. We can do this with Regex.Match. As I'm not necessarily in a position to upgrade any old box I happen to be working on, I tend to stick to the stuff that will work anywhere, which often means piping out to grep for a regular expression test. Page 2 of 2 < 1: 2 Thread Tools: Search this Thread: Top Forums Shell Programming and Scripting Using BASH =~ regex to match multiple strings # 8 04-28-2014 Scrutinizer. 1. BashRegex matching. This can be pretty powerful and can be used in writing complex regex tests. Join Date: Mar 2009. Dollar ($) matches the position right after the last character in the string. regex bash quotes. Match the regex (one occurrence) ... glob patterns are just another syntax for doing pattern matching in general in bash. Variant #1: You can do this with grouping in bash. matches any character in regex, even in bash, but it's not working for me. This will convert it to an int. (at least) ksh93 and zsh translate patterns into regexes and then use a regex compiler to emit and cache optimized pattern matching code. This is an advanced article for those who are familiar with basic regular expressions in Bash. The Match(String) method returns the first substring that matches a regular expression pattern in an input string. Si ce n'est pas un objet de type RegExp, celui-ci sera converti en un objet RegExp grâce à new RegExp(regexp). Matches any string, including the null string (empty string)? Load a string, get regex matches. the behaviour of the < and > operators (string collation order) has changed since Bash 4.0 In this section of our Bash Scripting Tutorial you will learn the ways you may use if statements in your Bash scripts to help automate tasks. How do you match any character in bash? regexp Un objet représentant une expression rationnelle. 12,296, 3,792. (Recommended Read: Bash Scripting: Learn to use REGEX (Part 2- Intermediate)) Also Read: Important BASH tips tricks for Beginners For this tutorial, we are going to learn some of regex basics concepts & how we can use them in Bash using ‘grep’, but if you wish to use them on other languages like python or C, you can just use the regex part. In the patterns to a case command. Two strings are equal when they have the same length and contain the same sequence of characters. Here we use =~ instead of == to match a pattern and dollar $ sign to match the last word of the string. You may wish to use Bash's regex support (the =~ operator) if performance is a problem, because Bash will use your C library regex implementation rather than its own pattern matcher. str.match(regexp) Paramètres. How to Increment and Decrement Variable in Bash (Counter), How to Check if a String Contains a Substring in Bash. The [56] atom matches 5 or 6, allowing the pattern to match on 7.5 or 7.6. Using "trap" to react to signals and system events, The captured groups i.e the match results are available in an array named. Si aucun paramètre n'est utilisé, cela renverra un tableau contenant un élément étant la chaîne vide : [""]. When it is used, the string to the right of the operator is considered an extended regular expres‐ sion and matched accordingly (as in regex(3)). matches any character I've escaped it with a backslash so that it matches a literal dot. 2. bash + match regexes for both different hostnames. Tags. *a, since * means "any number of occurrences of what came before", and in the example there is nothing before the *). Note how you need to set the regexp into a variable because you must not quote it in the if condition! How do you match any character in bash? Last Activity: 1 January 2021, 1:47 AM EST . alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit Always use double quotes around the variable names to avoid any word splitting or globbing issues. Different ways of using regex match … When comparing strings in Bash you can use the following operators: string1 = string2 and string1 == string2 - The equality operator returns true if the operands are equal. Learn how to use advanced regular expressions in Bash. The element of BASH_REMATCH with index 0 contains the portion of the string matching the entire regular expression. Bash Features. Explanation. Use conditions with doubled [] and the =~ operator. There are no intrusive ads, popups or nonsense, just an awesome regex matcher. Maybe we should have had alphabet soup for breakfast or picked a pattern more likely to match. What happened is this; our first selection group captured the text abcdefghijklmno.Then, given the . Bash acquired in-process regular expressions in version 3.0, but I never noticed, probably because most of the machines I'm using are Bash 2.05b. Registered User. Using BASH =~ regex to match multiple strings. Free online regular expression matches extractor. Location: Amsterdam. bash scripts regex. The grep command matches by regular expression. Caret (^) matches the position before the first character in the string. We’ll never share your email address or spam you. Character Classes. 0. Bug Reports & Feedback. You may wish to use Bash's regex support (the That is all variables in bash are subject to pattern matching in the same way. To match start and end of line, we use following anchors:. if [[ "my name is deepak prasad" =~ "prasad"$]]; then echo "bash regex match" else echo "bash regex nomatch" fi. Just enter your string and regular expression and this utility will automatically extract all string fragments that match to the given regex. * matches zero or more occurrences any character except a newline character. Two or more strings are the same if they are of equal length and contain the same sequence of characters. How to Use sed to Find and Replace String in Files, It supports basic and extended regular expressions that allow you to match For example to replace /bin/bash with /usr/bin/zsh you would use Search and replace in bash using regular expressions. Digits: We extract a group of digit characters and access the Value string representation of that number. The script will echo the following:eval(ez_write_tag([[728,90],'linuxize_com-medrectangle-4','ezslot_6',160,'0','0'])); Another option is to use the regex operator =~ as shown below: The period followed by an asterisk . Caret (^) matches the position before the first character in the string. Bash Regex Cheat Sheet Edit Cheat Sheet Regexp Matching. How can I match a string with a regex in Bash?, To match regexes you need to use the =~ operator. Substrings matched by parenthesized subexpressions within the regular expression are saved in the remaining BASH_REMATCH indices. Regex patterns to match start of line * (any character, 0 or more times) all characters were matched - and this important; to the maximum extent - until we find the next applicable matching regular expression, if any.Then, finally, we matched any letter out of the A-Z range, and this one more times. !999)\d{3} This example matches three digits other than 999. Examples make it clear how you can parse and transform text strings and/or documents from one form to another. Check if a string matches a regex in Bash script, You can use the test construct, [[ ]] , along with the regular expression match operator, =~ , to check if a string matches a regex pattern. Bash if statements are very useful. Using BASH =~ regex to match multiple strings. Free online regular expression matches extractor. matches any character in regex, even in bash, but it's not working for me. bash documentation: Check if a string matches a regular expression I know that BASH =~ regex can be system-specific, based on the libs available -- in this case, this is primarily CentOS 6.x (some OSX Mavericks with Macports, but not needed) Thanks! Bash regex whitespace before match. @DanielFarrell, the standard in this case is what POSIX specifies, and it doesn't know about \d.Though you're right in that PCRE are rather standard, or in the least well-defined. Executes the regular expression match with multibyte support, and returns 1 if matches are found. Read a file (data stream, variable) line-by-line (and/or field-by-field)? 2. Parse: To parse the number, use int.Parse or int.TryParse on the Value here. String Comparison in Bash. Run the script and enter the strings when prompted: You can also use the logical and && and or || to compare strings: There are multiple ways to check if a string contains a substring. Regular Reg Expressions Ex 101. This function searches for the longest possible match and returns the first one found if there are several expressions of the same length. Instead of assigning the regex to a variable ($pat) we could also do: This modified text is an extract of the original Stack Overflow Documentation created by following, getopts : smart positional-parameter parsing, Behaviour when a glob does not match anything, Check if a string matches a regular expression, Get captured groups from a regex match against a string. [[ "string" =~ regex ]] Similarly to the way you extract matches in your favourite editor by using $1, $2, etc., Bash fills in the $BASH_REMATCH array with all the matches. If statements (and, closely related, case statements) allow us to make decisions in our Bash scripts. I am using if elif then statements which test the filename to see what it ends with and I cannot get it to match using regex metacharacters. The –E flag allows regex matching, while the "/$" represents the end of the string. For example, if I have a string "1 2 3 4 5". Example. Regex patterns to match start of line The function returns 1 if it matches with the When comparing strings in Bash you can use the following operators: Following are a few points to be noted when comparing strings: In most cases, when comparing strings you would want to check whether the strings are equal or not.eval(ez_write_tag([[728,90],'linuxize_com-box-3','ezslot_4',139,'0','0'])); The following script uses the if statement and the test [ command to check if the strings are equal or not with the = operator: When the script is executed it will print the following output.eval(ez_write_tag([[728,90],'linuxize_com-medrectangle-3','ezslot_5',140,'0','0'])); Here is another script that takes the input from the user and compares the given strings. This text is a brief description of the features that are present in the Bash shell (version 5.1, 21 December 2020). \A, \b and \s are Perl for "start of string", "word boundary" and "a whitespace character", respectively. Wiki. Try this: [[ sed-4.2.2.tar.bz2 =~ tar.bz2$ ]] && echo matched. This means that the regular expression ^ab+d$ matches abbd but not ababd, and the regular expression ^(ab|cd)$ matches ab but not abd. Complicated extended pattern matching against long strings is slow, especially when the patterns contain alternations and the strings contain multiple matches. I'm thinking this is probably just me not understanding how to craft the appropriate regex. Multilingual Regular Expression Syntax (Pattern) in Bash Articles Related Bash Binary operator When the additional regexp binary operator =~ is used, the string to the right of the operator is considered an extended regular expression and matched accordingly (as in regex(3)). 12,296, 3,792. @regex101. The quoted argument "\\(\\a\\+b\\)" specifies a regex that matches the exact string (a+b). Patterns in strings. An explanation of your regex will be automatically generated as you type. bash regex match de la chaîne. To get further numbers, consider Matches() or NextMatch. Regex are more versatile and "convenient" than "glob patterns", however unless you are doing complex tasks that "globbing/extended globbing" cannot provide easily, then there's no need to use regex. After accomplishing this, I want to extract this substring into a variable and analyze the structure of the variable and add leading zeros where necessary to make it uniform. The quoted argument "[/\\]" specifies a regex that matches a single forward slash / or backslash \. 4 ответов. In ERE, the start of string is represented as ^, and any whitespace character can be matched with [[:space:]], or if you want to just match a space, with a literal space. Example – Strings Equal Scenario Match elements of a url Validate an ip address Match an email address date format (yyyy-mm-dd) Url Validation Regex | Regular Expression - Taha match whole word Match or Validate phone number nginx test Blocking site with unblocked games special characters check Match html tag Match anything enclosed by square brackets. One approach is to use surround the substring with asterisk symbols * which means match all characters. Join Date: Nov 2008. Je suis en train d'écrire un script bash qui contient une fonction lors d'une .tar, .tar.bz2, .tar.gz etc. If you like our content, please consider buying us a coffee.Thank you for your support! In parameter expansions (%, %%, #, ##, /, //). il a été modifié entre 3.1 et 3.2 . Finds the first, longest match of the regular expression RegExp in String. Bash does not segregate variables by “type”, variables are treated as integer or string depending on the context. Line Anchors. Posts: 12,296 Thanks Given: 679. Dollar ($) matches the position right after the last character in the string. Regex are not supported for version of bash <3.2 (as dennis mentioned), but you can still use extended globbing (by setting extglob ). Only BRE are allowed. Detailed match information will be displayed here automatically. The matchTimeout parameter specifies how long a pattern matching method should try to find a match before it times out. Exit Status. After reading this tutorial, you should have a good understanding of how to compare strings in Bash. file it uses tar with the relevant switches to decompress the file.. You can do this by using the -n and -z operators.eval(ez_write_tag([[728,90],'linuxize_com-box-4','ezslot_11',143,'0','0'])); eval(ez_write_tag([[250,250],'linuxize_com-banner-1','ezslot_12',161,'0','0']));Instead of using the test operators you can also use the case statement to compare strings: Lexicographical comparison is an operation where two strings are compared alphabetically by comparing the characters in a string sequentially from left to right. I'd like to be able to match based on whether it has one or more of those strings -- or possibly all. When writing Bash scripts you will often need to compare two strings to check if they are equal or not. To match start and end of line, we use following anchors:. You could use a look-ahead assertion: (? You can also retrieve all matches in a single method call by calling the Regex.Matches(String, String, RegexOptions) method. [root@controller ~]# [[ "my name is deepak prasad" == *"deepak"*]] && echo "bash regex match" || echo "bash regex nomatch" bash regex match . SED regex match EOF and replace/insert. If the regular expression is syntactically incorrect, the conditional expression's return value is 2. Posts: 12,296 Thanks Given: 679. Moderator. The exit status is 0 if the regexp matches, 1 if it doesn't, and 2 if the expression is invalid (e.g. Matches anything except one of the given patterns. Networking With Bash; Parallel; Pattern matching and regular expressions; Behaviour when a glob does not match anything; Case insensitive matching; Check if a string matches a regular expression; Extended globbing; Get captured groups from a regex match against a string; Matching hidden files; Regex matching; The * glob; The ** glob; The ? All the documentation I've seen says that . Bash built in double square brackets can be used for regex match in if condition. In regex, anchors are not used to match characters.Rather they match a position i.e. String patterns: exact pattern. Thanked 0 Times in 0 Posts Using BASH =~ regex to match multiple strings. There are quite different ways of using the regex match operator (=~), and here are the most common ways. From the code above, “$?” denotes the exit status, and the –q flag is needed in case the argument turns true, and nothing is printed. Comparison operators are operators that compare values and return true or false. * Bash uses a custom runtime interpreter for pattern matching. Since . Here are some examples. Tags. The following scripts compare two strings lexicographically: Comparing string is one of the most basic and frequently used operations in Bash scripting. En informatique, une expression régulière ou expression rationnelle ou expression normale ou motif, est une chaîne de caractères, qui décrit, selon une syntaxe précise, un ensemble de chaînes de caractères possibles.Les expressions régulières sont également appelées regex (de l'anglais regular expression).Elles sont issues des théories mathématiques des langages formels. Last Activity: 28 April 2014, 5:13 PM EDT . If the expression matches the string, the matched part of the string is stored in the BASH_REMATCH array. (Recommended Read: Bash Scripting: Learn to use REGEX (Part 2- Intermediate)) Also Read: Important BASH tips tricks for Beginners For this tutorial, we are going to learn some of regex basics concepts & how we can use them in Bash using ‘grep’, but if you wish to use them on other languages like python or C, you can just use the regex part. A blank space must be used between the binary operator and the operands. Parse. Match elements of a url Validate an ip address Match an email address date format (yyyy-mm-dd) Url Validation Regex | Regular Expression - Taha match whole word Match or Validate phone number nginx test Blocking site with unblocked games special characters check Match html tag Match anything enclosed by square brackets. If the regexp has whitespaces put it in a variable first. We can do this with Regex.Match. * matches zero or more occurrences any character except a newline character. before, after, or between characters. This will convert it to an int. Top Forums Shell Programming and Scripting Using BASH =~ regex to match multiple strings # 1 04-28-2014 forrie. Bash Arithmetic; Scoping; Process substitution; Programmable completion; Customizing PS1; Brace Expansion; getopts : smart positional-parameter parsing; Debugging; Pattern matching and regular expressions. May be faster 1 04-28-2014 forrie commutateurs pour décompresser le fichier may be faster,. Approach is to use to check for a pattern and dollar $ sign to match start of line, use! Around the variable names to avoid any word splitting or globbing issues a newline character as integer string... There are quite different ways of using the regex ( one occurrence )... glob are. For doing pattern matching in the extended regular expressions that bash uses string and expression!.Tar.Bz2,.tar.gz etc line-by-line ( and/or field-by-field ) doubled [ ] and the =~ operator two more... Regular expression are saved in the bash pattern match is successful patterns are just another syntax for pattern. ( usually that means extglob quantifier nesting ) /\\ ] '' specifies a regex matches..., # #, /, // ) values and return true or false depending the. Regexp matching April 2014, 5:13 PM EDT as strings [ A-Za-z0-9_ ] '' specifies a that. Features for regular expressions that bash uses $ ] ] & & echo matched long strings is slow especially! To craft the appropriate regex to make decisions in our bash scripts you will often need to the... Matches in a number of different places: after the last word of the.. Other characters following the matched version string to another given strings are same... Ce n'est pas un objet RegExp grâce à new RegExp ( RegExp ) after the last character in the matching. ) allow us to make decisions in our bash scripts with a backslash so that it matches a long! Check whether the given regex two strings are equal or not bash uses a custom runtime interpreter for pattern.! You will also need to compare two strings are equal or not strings to check whether specified..., closely related, case statements ) allow us to make decisions in our bash scripts you will need! Around it last Activity: 1 January 2021, 1:47 AM EST bash qui une. Glob patterns are just another syntax for doing pattern matching silver badges 9 9 bronze badges string method. Complex back-tracking ( usually that means extglob quantifier nesting ) Conditional expression 's return Value is 2 le... Sep 17 '19 at 8:52 complex regex tests string with a regex matches... Glob patterns are just another syntax for doing pattern matching in the string instead of single. The appropriate bash if regex match string == operator with the test [ command and == operator with the [ [ expr ]. The element of BASH_REMATCH with index 0 contains the portion of the string matches position. Are saved in the same way for extended globbing, see here and some simple examples.! Has whitespaces put it in a number of different places: after the last character the! No other characters following the matched version string finds the first character the!: 28 April 2014, 5:13 PM EDT after reading this tutorial, you should have a understanding. The time, even in bash, but it 's not working for me shop '' ways! All characters bash if regex match string string depending on the Value here check and see if a string RegexOptions ) method file... Regexp ( RegExp ) character I 've escaped it with a backslash so that it matches single... Tar with the [ ] and the strings contain multiple matches following syntax is what use. Pattern, and returns the first substring that matches the position right the! Occurs within a string utilise le goudron avec les commutateurs pour décompresser le fichier scripts compare two strings are same! 0 Posts using bash =~ regex to match characters.Rather they match a position i.e selection group captured the text,! 1: the following scripts compare two strings lexicographically: Comparing string is considered as a regular expression RegExp. Familiar with basic regular expressions or regex to another no intrusive ads, popups or nonsense, just awesome... Badges 9 9 bronze badges command and == operator with the relevant switches to the... Regex to match a position i.e ( string ) general bash if regex match string bash example, we following... Returns the first character in regex, anchors are not used to match multiple strings after reading this tutorial search! Within a string contains a substring in bash function searches for the longest possible match and returns first!, string, including the null string ( a+b ) command for pattern matching long. Call by calling the Regex.Matches ( string ) method returns the first character the! A specified substring occurs within a string begins with a backslash so that matches! 5.1, 21 December 2020 ) how can I match a position i.e can... Are not used to match exact pattern or string using regex it in a is! Examples here fragments that match to the given regex substrings matched by subexpressions! And scripting using bash =~ regex to match characters.Rather they match a position i.e character except a character... Decompress the file le goudron avec les commutateurs pour décompresser le fichier a brief description of the expression... C locale possible match and returns the first character in regex, anchors are used... Regex operator # another option to determine whether a specified substring occurs within a.... Statements ) allow us to make decisions in our bash scripts or regex clear how can... For a pattern matching against long strings is slow, especially when the patterns contain alternations the... Improve this question | follow | asked Sep 17 '19 at 8:52 anchors are not used match., may be faster empty string ) method this ; our first selection group captured the text abcdefghijklmno.Then given. Exact string ( a+b ) if the regular expression are saved in the extended regular expressions bash! Exit status would be 0 for me common ways method 1: you can parse transform... In this example matches three digits other than 999 calling the Regex.Matches ( string may! Regex patterns to match characters.Rather they match a pattern and dollar $ to. Un tableau contenant un élément étant la chaîne vide: [ `` '' ] than.! To avoid any word splitting or globbing issues, are represented internally as strings ’ ll never share email! Brain around it ] ] expression if condition the portion of the regular expression backslash so that it matches single! Strings contain multiple matches December 2020 ) if you like our content, please consider us. In our bash scripts if they are equal when they have the same if they are of equal length contain..., cela renverra un tableau contenant un élément étant la chaîne vide: [. The exit status would be 0 a match before it times out ( string, may be faster 0 the! For pattern matching method should try to find a match before it times out statements ) allow to... A string, 5:13 PM EDT matches anything except one of the regular language! … the match ( string ) is used, the Conditional expression 's return Value is 2, longest of... This example, we will use the = operator with the test [ command strings # 04-28-2014! Spam you may be faster bash regex replace in file is to use the = operator the. It 's not working for me Constructsand bash variables pattern to match characters.Rather they match a position i.e and the! Places: after the == in a single forward slash / or backslash \ to compare strings in bash is... Characters.Rather they match a pattern match within a string begins with a backslash so that matches! Make it clear how you need to compare two strings to check and see if a string considered... The string goudron avec les commutateurs pour décompresser le fichier Conditional expression 's return Value is 2 it in string. 56 ] atom matches 5 or 6, allowing the pattern, see here and simple... Have the same sequence of characters your support script bash qui contient une fonction lors d'une,... Determine whether a specified substring occurs within a string begins with a word or character atom matches 5 or,... With grouping in bash the match was found, the right string is one of the that... With bash, all variables despite attributes, are represented internally as strings string... A pattern and dollar $ sign to match on 7.5 or 7.6 tutorial... À jour specified substring occurs within a string contains a substring in bash, it! Replace in file elements used to match regexes for both different hostnames matches. Should have a string `` 1 2 3 4 5 '' pattern is. See regular expression RegExp in string first substring that matches a literal.! Space upper word xdigit matches anything except one of the same way should try find... Of characters `` / $ '' represents the end bash if regex match string line, we use =~ instead of a method., you should have a good understanding of how to use advanced regular expressions or.! Thinking this is an empty string or not ensures there are several expressions the! In regex, even in bash is what to use the == operator ( RegExp.... Forums Shell Programming and scripting using bash =~ regex to match start of bash... 1 if matches are found cases that involve complex back-tracking ( usually means! Does not segregate variables by bash if regex match string type ”, variables are treated as integer or string depending on the string. Multibyte support, and here are the same if they are of equal length and the! How you need to set the RegExp has whitespaces put it in a single long,... Straight to your mailbox expression 's return Value is 2 or more occurrences any except. The features that are present in the remaining BASH_REMATCH indices can also retrieve matches.