The right-hand operand is the pattern variable, but unquoted. This uses bash's regular expression conditional operator to test the argument against: Thanks for contributing an answer to Unix & Linux Stack Exchange! Regex not working in HTML5 pattern. The question does not have to be directly related to Linux and any language is fair game. Comments. If the regular expression remains constant, using this can improve performance.Or calling the constructor function of the RegExp object, as follows:Using the constructor function provides runtime compilation of the regular expression. Are Random Forests good at detecting interaction terms? Simple Example - Use Bash Shell to Match IP address The shell is a programming environment. I am writing script to which should deploy application which has following string match 1001--. This module is part of ansible-base and included in all Ansible installations. The string will actually be a part of a hostname, for example "one-hostname" or something like that. regex,html5. Without this option, these anchors match at beginning or end of the string. Programming :: ! The examples are rather unclear. This forum is for all programming questions. 3. In this tutorial we will look =~ operator and use cases. The BASH extension of "[", i.e. It returns 0 (success) if the regular expression matches the string, otherwise it returns 1 (failure). If you just want to remove www or ftp, you can use Parameter expansion: var=${HOSTNAME#www.} What part of the address do you want? The subroutine returns 1 if the string s matches the last compiled regular expression, 0 if the string s failed to match the last compiled regular expression, and -1 if the compiled regular expression was invalid (indicating an internal error). NIC: We can provide the different network interface card as an input to the network command. You can do the regex match using Shell script. Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. The IPv4 and IPv6. You are currently viewing LQ as a guest. I'm not trying to validate them because it's safe enough to assume traceroute is valid (i.e. In bash speak true means it exits with a zero status, anything else is false. Bash script programming: how to match pattern in string? I Googled for tutorials, and I'm a bit overwhelmed. In other … Host name is the identifier of a system in the network. They can be useful during information validation, to ensure that data is in a specified format. The element of BASH_REMATCH with index n is the portion of the string matching the nth parenthesized subexpression. bash extended patterns are enabled within [[ ... ]]; so you can do. An expression is a string of characters. Post Posting Guidelines Formatting - Now. var=${var#ftp.} Hostname/IP … Regex not working in HTML5 pattern. is not outputting something like 999.999.999.999.I'm trying the following regex: March 13, 2016 No Comments BASH Shell, hacker rank, online judge, regex. it's not available in older bash versions). You construct a regular expression in one of two ways:Using a regular expression literal, which consists of a pattern enclosed between slashes, as follows:Regular expression literals provide compilation of the regular expression when the script is loaded. 0. For example, statement should match "Tunnel3" or "Serial0/1" but shouldn't match "Serial0\1.1" (doesn't include dot ".") *)?$' replace: '\1server1.nixcraft.com\2' backup: yes Finding and replacing text or IP address with Ansible. ^ for the start, $ for the end), match at the beginning or end of each line for strings with multiline values. Expressions may be combined using the following operators, listed in decreasing order of precedence: Tag Description ( expression) Returns the value of expression. For Not Matching Bash Regex? this changed: host = raspberrypi. Regular Expression Matching (REMATCH) Match and extract parts of a string using regular expressions. regex,html5. to throw error who are not matching standard hostname. Programming :: Awk Computed Regex Not Working As Expected Programming :: Program To Use Grep W/regex? In addition to doing simple matching, bash regular expressions support sub-patterns surrounded by parenthesis for capturing parts of the match. I have hostname like following. The status of a command/function is stored in the bash variable "$?". Host name can be get with different ways in Linux. Regular Expression to Check whether a string is a properly formatted hostname. Regular Expression flags; Test String. The strings passed to both and may have trailing or embedded newline characters; they are terminated by nulls. #!/bin/bash # Test an IP address for validity: # Usage: # valid_ip IP_ADDRESS # if [[ $? Viewed 22k times 5. The stuff matched by the last part of your regex (which is presumably meant to match path, query string, and anchor all together) can overlap with the hostname (both \w and - areUsing regex to match specific numbers of sub-directories in a URL can be very helpful for Google Analytics. Matched IP addresses can be extracted from a file using grep command.. Simply put, a regular expression allows us to search for a pattern within a string by use of meta-characters. Bash always evaluate Regex as true. A regular expression is a pattern that describes a set of strings. Browse other questions tagged bash regular-expression or ask your own question. I am trying to match IP addresses found in the output of traceroute by means of a regex. Bash check if a string contains a substring . Is it my fitness level or my single-speed bicycle? Should I "take out" a double, using a two card suit? Loading… 0 +0; Tour Start here for a quick overview of the site Help Center Detailed … Grep understands two different versions of regular expression syntax: "basic" and "extended." By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. ansible.builtin.replace – Replace all instances of a particular string in a file using a back-referenced regular expression; ansible.builtin.replace – Replace all instances of a particular string in a file using a back-referenced regular expression¶ Note. The IPv4 contains 4294967296 (2^32) … means that we will count all lines containing at least one character, space, blank, tab, etc.. In this article you’ll find a regular expressions themselves and an example of how to extract matched IP addresses from a file with the grep … hello, I am writting a regular expression that intend to match any tunnel or serial interface but it doesn't mtach any serial sub-interface. Regular Expressions in grep - Learn how to use regular expressions (regex) in grep to search for text/words in … Assertions check for a match, but do not count towards the total match length. It is convenient, but with a pitfall. Programming :: ! Example. Featured on Meta A big thank you, Tim Post ... Regex match fix string in hostname. Applications of Hamiltonian formalism to classical mechanics. How to Valid IPv6 Addresses using BASH and Regex ? Match string not containing string … However, [[is bash’s improvement to the [command. $ cat /etc/hostname Get Host name By Echoing Host name File Get … Visit Stack Exchange. Here is my code Code: #!/bin/bash [SOLVED] Bash - Basic script to check hostname matches More information about regex command cna be found in the following tutorials. The following bash script contains a bash function which returns true if it is passed a valid IP address and false otherwise. Tags: bash, hacker rank, ipv4, ipv6, online judge, regex, regular expression. Piano notation for student unable to access written and spoken language. General :: Bash Scripting - Executes A Few Perl Scripts - Create A New Array And Take The Hostname; Programming :: Regex To Read An Ip? So, … The regular expressions recognized are described in … The domain name should be between 1 … This blog shows how to make use of this operator and also demonstrates the pitfall. 18.1. The problem with your regular expression is that you tell it that it must first match your string with zero to infinity amounts of \w which "Matches any word character including underscore", followed by a literal dot ..(\w*\.in the case of test-test.com01 it does not match because of the hyphen, so if you change it to match also -then it will work the way you want it to: \(\([a-z_-]*\.[a-z_-]*\)\|\([a-z_]*\.[a-z_-]*\. The grep command becomes more powerful when we use regular expressions (regexes). Linux bash provides a lot of commands and features for Regular Expressions or regex. I think it also carries a very large load of graphical baggage -- sort of like Tk (tcl/Tk). Types of regex. The valid domain name must satisfy the following conditions: The domain name should be a-z or A-Z or 0-9 and hyphen (-). We saw some of those patterns when introducing basic Linux commands and saw how the ls command uses wildcard characters to filter output. Active 4 years, 8 months ago. *} The following example provides an illustration. How are you supposed to react when emotionally charged (for right reasons) people make inappropriate racial remarks? R-egular E-xpression MATCH-ing (the first many times I read the word "rematch", I just could not help my thoughts drifting back to Hulk Hogan taking on André the Giant at WrestleMania IV- those were the days...) is performed using commands on the form: A regular expression is a pattern that describes a set of strings. If the Regex.Match method fails to match the regular expression pattern, it returns a Match object that is equal to Match.Empty. Here are some regular expressions that will help you to perform a validation and to extract all matched IP addresses from a file.. bash: routine outputting both matches and non-matches separately??? By joining our … A Brief Introduction to Regular Expressions. What's the fastest / most fun way to create a fork in Blender? Regular expression fragments can be grouped using parentheses. http://wiki.bash-hackers.org/commands/classictest, http://wiki.bash-hackers.org/syntax/...nal_expression, http://mywiki.wooledge.org/ArithmeticExpression, Bash script to suppress matches in two column list. As I said, when you quote the regular expression, it's taken literally. The pattern attribute has to match the entire string. Host name file /etc/hostname ... apache apt bash centos cpu database directory disk dns fedora file file system find firefox ftp grep html http https ip linux list log mysql network nmap ntfs password php process programming python regex regular expression security shell ssh … So now, you should be able to use grep -E 'that … Host name information is stored in a file /etc/hostname. Regular expression to extract hostname from fully qualified domain name. Regular expression fragments can be grouped using parentheses. Regular expressions are constructed analogously to arithmetic expressions, by using various operators to combine smaller expressions. Any suggestions would be appreciated. Can this equation be solved with whole numbers? Since version 3 of bash (released in 2004) there is another option: bash's built-in regular expression comparison operator "=~". If you group a certain sequence of characters, it will be perceived by the system as an ordinary character. The pattern attribute has to match the entire string. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Password: Programming This forum is for all programming questions. Assertions check for a match, but do not count towards the total match length. General :: Bash Scripting - Executes A Few Perl Scripts - Create A New Array And Take The Hostname; Programming :: Regex To Read An Ip? ... How to Get List of IP addresses in BASH using hostname and tr commands? Validating Domain Names; Check valid (sub)domain with regex in bash ; Bash subdomain regex validation never matches; By Peter | 5 comments | 2013-03-07 10:40. Given string str, the task is to check whether the given string is a valid domain name or not by using Regular Expression. var=${var%%. The =~ operator is similar to match() function. The macro problem with microservices. Leave a ReplyCancel reply. I'm curious to know what the output is if you echo both of them to the terminal: You'll notice I made a couple of other code changes too. Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star? For example, a ZIP code must consist of five digits, and … 1. return value from awk. Regular expressions are constructed analogously to arithmetic expressions, by using various operators to combine smaller expressions. Programming :: Find With A Regex Path? The [and [[evaluate conditional expression. "[[", supports an additional operator "=~" for regexp matching. The =~ operator is similar to match() function. The Overflow Blog Podcast 288: Tim Berners-Lee wants to put you in a pod. In other … – Chris Down Jan 31 '14 at 12:27 It also returns false for 0111.0111.0111.0111 or 08.08.08.08 (that one with a value too great for base error) – Stéphane … How to check if a package is installed from Bash? As far as I know, the =~ operator is bash version specific (i.e. Programming :: Find With A Regex Path? Many different applications use different types of regex in Linux, like the regex included in … I've recently written about using bash arrays and bash regular expressions, so here's a more useful example of using them to test IP addresses for validity.. To belabor the obvious: IP addresses are 32 bit values written as four numbers (the individual bytes of … Online regex tester, debugger with highlighting for PHP, PCRE, Python, Golang and JavaScript. Get Host name By Echoing Host name File. host = myrpi. Asking for help, clarification, or responding to other answers. In GNU grep, there is no difference in available functionality between basic and extended syntaxes. The re and fe above are regular expressions and filename expressions, intended to show the different syntax, and how one works and the other does not. At this point we can go back to our original problem, which is to search for all files starting with 'A' and ending with 'K'.Here is a list of meta-characters we need to use in order to accomplish this task: "^", ". In GNU grep, there is no difference in available functionality using either syntax. grep understands three different versions of regular expression syntax: "basic," "extended" and "perl." Since version 3 (circa 2004), bash has a built-in regular expression comparison operator, represented by =~. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Programming :: Program To Use Grep W/regex? This … To learn more, see our tips on writing great answers. Notices: Welcome to LinuxQuestions.org, a friendly and active Linux Community. grep, expr, sed and awk are some of them. The domain name should be between 1 and 63 characters long. The matches are assigned to … Another example to replace hostname server1.cyberciti.biz with server1.nixcraft.com in /etc/hosts: - replace: path: /etc/hosts regexp: '(\s+)server1\.cyberciti\.biz(\s+. [SOLVED] Bash-REGEX for validating computername User Name: Remember Me? Angular momentum of a purely rotating body about any axis. This is a synonym for the test command/builtin. My pattern starts with *-1001- where I'm assuming that you don't want to match 11001 or 21001 etc. 3. This is a synonym for the test command/builtin. How to Valid IPv6 Addresses using BASH and Regex ? The [and [[evaluate conditional expression. fly wheels)? Using sed for multiple matches instead matching whole file. Tags: bash, hacker rank, ipv4, ipv6, online judge, regex, regular expression. I got something out of this, namely dtksh, thanks to Perderabo.It's a bit tricky to find. Hi, I'm learning bash and want to write a very basic bit of code to check the server hostname against a variable. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers . The BASH extension of "[", i.e. Example: script should match following hostname. Did Trump himself order the National Guard to clear out protesters (who sided with him) on the Capitol on Jan 6? Do sinners directly get moksha if they die in Varanasi? The following regular expressions match IPv4 addresses.. Host name is generally put in the /etc/hostname file. This is to be added to an auto_start shell script start up our application on Linux workstation and servers. Making statements based on opinion; back them up with references or personal experience. awk documentation: Regexp Patterns. rev 2021.1.8.38287, Sorry, we no longer support Internet Explorer, The best answers are voted up and rise to the top. There are many tools we can use in *nix-based systems to find and manipulate text. You can do the regex match using Shell script. [Different Network Command] [NIC] [Option] [Hostname/IP Address] Different Network Command: We can use different network level keyword/command in it like netstat, ifconfig, traceroute, dig, route, etc. I need to get: example.ru My scipt: #!/bin/bash hostname=example.com01 e... Stack Exchange Network. For Not Matching Bash Regex? The IPv4 is 32-bit that contains 4 bytes. The element of BASH_REMATCH with index 0 is the portion of the string matching the entire regular expression. This blog shows how to make use of this operator and also demonstrates the pitfall. Would Mike Pence become President if Trump was impeached and removed from office? Bash also have =~ operator which is named as RE-match operator. Simple Example - Use Bash Shell to Match IP address The shell is a programming environment. More details i want to do if then.. and return exit status code with $? And the array is saved at ${BASH_REMATCH[1]}, ${BASH_REMATCH[2]} etc. forrie: View Public Profile for forrie: Find all … IP Addresses consist of two kinds. : m: For patterns that include anchors (i.e. !Well, A regular expression or regex, in general, is a But in this case the match word will be at the beginning ^one. Top Regular Expressions. The string will actually be a part of a hostname, for example "one-hostname" or something like that. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. What are the earliest inventions to store and release energy (e.g. maddog. Your email address will not be … Given string str, the task is to check whether the given string is a valid domain name or not by using Regular Expression. 2. Bash's regular expression comparison operator takes a string on the left and an extended regular expression on the right. Programming :: Awk Computed Regex Not Working As Expected For example, X.Y.Z.U where four digits (0 to 255) are separated by dots. Option: We can provide the different flags as options that are compatible with Network command. Viewed 627 times 0. March 13, 2016 No Comments BASH Shell, hacker rank, online judge, regex. The == operator in [[ ... ]] is a pattern matching operator. Ask Question Asked 2 years, 1 month ago. Linux is a registered trademark of Linus Torvalds. Additionally, you can substitute captured regex groups using numberedDescription: Matching a URL or hostname against a regular expression that contains an unescaped dot as part of the hostname might match more hostnames than expected. Bash check if a string contains a substring . I am a beginner to commuting by bike and I find it very tiring. The python regexp is using the extended regular expression syntax which comes from the egrep command in the 70s (though the {...} part was added later, and actually in grep before egrep).. POSIX have consolidated the grep and egrep commands (egrep is now grep -E) in the 90s and standardized the {x,y} operator (which wasn't available in the earlier egreps).. And the array is saved at ${BASH_REMATCH}, ${BASH_REMATCH} etc. ", "*" and "$". For more information about the elements that can form a regular expression pattern, see Regular Expression Language - Quick Reference. Bash's regular expression comparison operator takes a string on the left and an extended regular expression on the right. Option Description Syntax Restrictions; i: Case insensitivity to match upper and lower cases. html. www-foo-1001-1-1.example.com. A web pod. Basic grep regexes. I need it check that there's a match, possibly doing something based on what it matched. The regular expression that you could use to capture the host name would be: S[0-9]+_([a-zA-Z0-9]*)[_-]HBA[0-9] The outcome is a match of all zones beginning with S that are followed by any combination of digits , followed by an underscore, the alphanumeric hostname (myComputer1Name), an underscore or hyphen, the capital letters HBA, and a single digit (0-9). A regular expression (regex) is a method of representing a string matching pattern. Bash based regex domain name validation; domain name regular expression not matching; Simplest way to verify if a given string is a valid FQDN name ; 8.15. Active 2 years, 1 month ago. There are some other gotchas and some platform specific issues, see the BashWiki for more info (see Portability Considerations). That allows interpretation of the variable's value as a pattern not a string. to. I wanted to change the name of my raspberrypi hostname in a conf file, but the above example did not work for me (it inserted the new name at the beginning, but left the old name, too) Here is the command I ended up using: sed -i “/^host =/c\host = myrpi” inputs_test.conf . I need it check that there's a match, possibly doing something based on what it matched. That is, … LinuxQuestions.org is looking for people interested in writing It only takes a minute to sign up. Are those Jesus' half brothers mentioned in Acts 1:14? Hot Network Questions As a beginner, how do I learn to … 3. [a-z_-]*\)\) ^ … -eq 0 ]]; then echo good; else echo bad; fi … You can use the Success property to determine whether the match was successful. Use of this, namely dtksh, thanks to Perderabo.It 's a bit overwhelmed Quick Reference the regular?. Find it very tiring ) ( regex ) is a registered trademark of the Open.. And non-matches separately??????????! Doing something based on what it matched patterns that include anchors ( i.e check! Rss reader valid_ip IP_ADDRESS # if [ [ $? `` expressions or regex at least one character,,... Of them * '' and `` $? `` patterns that include anchors ( i.e tester... Military legally refuse to follow a legal, but do not count towards the total match length connect using! Rotating body about any axis Success ) if bash regex match hostname regular expression on the left and an extended expression! Extension of `` [ ``, `` * '' and `` extended '' and `` $.! Double, using a two card suit can be get with different in... For patterns that include anchors ( i.e your RSS reader column list grep command more. Using sed for multiple matches instead matching whole file, `` * '' and `` perl. in... Used in a file /etc/hostname an additional operator `` =~ '' for regexp.... They can be extracted from a file ( bash ) ( regex ) a. Extended patterns are enabled within [ [ $? `` that describes a set strings... Is the pattern attribute has to match pattern in string it exits with zero... [ [ is bash specific syntax and it will not work with:... By dots i want to do if then.. and return exit status code with $?.... Get the domain name or not by using various operators to combine smaller expressions a. Information validation, to ensure that data is in a pod create a fork in Blender purely! Server hostname against a variable, anything else is false out protesters ( who sided with )! To access written and spoken language zero status, anything else is false a long list of IP in... Similar to match the entire regular expression ( regex ) is a question and site! And included in all Ansible installations ) people make inappropriate racial remarks unix & Linux Stack Exchange a! Month ago Portability Considerations ) to create a fork in Blender a practical way to list every character used a. President if Trump was impeached and removed from office terms of service, privacy and. 2021.1.8.38287, Sorry, we no longer support Internet Explorer, the answers... Assuming that you do n't want to remove www or ftp, you agree our! People make inappropriate racial remarks the top unix & Linux Stack Exchange ;... In * nix-based systems to find and manipulate text MST connect monitors using 'displayPort! And extract parts of a string matching the entire string `` 'displayPort ' to 'mini displayPort ' `` only! Expression match... ] ] is a registered trademark of the Open group should be between 1 63. Following is bash ’ s improvement to the bash regex match hostname a properly formatted hostname 's regular matching... Element of BASH_REMATCH with index 0 is the pattern variable, but order! Beginning ^one both and may have trailing or embedded newline characters ; they are terminated nulls! The fastest / most fun way to create a fork in Blender possibly doing based... For all programming questions syntax and it will not be … simple example use... Return exit status code with $? `` Ansible installations and release energy ( e.g to a! ( for right reasons ) people make inappropriate racial remarks Editorials, Articles, Reviews, and i 'm that... Pattern matching operator exist while limiting the upper character count systems to find all files containing strings! About the elements that can form a regular expression match Post... regex match using script! You just want to do if then.. and return exit status code with $?.! Left and an extended regular expression comparison operator takes a string this operator and also demonstrates the pitfall ] a! Extract hostname from fully qualified domain name or not by using various operators to combine smaller.! Extension of `` [ ``, i.e operator which is named as RE-match operator www. the! Question does not bash regex match hostname to tweak the regular expression syntax: `` basic, '' `` ''. Replace: '\1server1.nixcraft.com\2 ' backup: yes Finding and replacing text or IP with..., $ { BASH_REMATCH [ 1 ] } etc follow a legal, but.! Extension of `` [ ``, i.e for more information about the elements that can form a regular language! [ is bash specific syntax and it will be at the beginning ^one is named RE-match... To extract all matched IP addresses can be extracted from a long list of string?... Beginning or end of the variable 's value as a pattern that describes a of... For planetary rings to be perpendicular ( or near perpendicular ) to the Network command have =~ operator bash... Hostname/Ip … online regex tester, debugger with highlighting for PHP,,... To clear out protesters ( who sided with him ) on the Capitol on Jan 6 when emotionally charged for., FreeBSD and other Un * x-like operating systems 'm learning bash and regex matching ( REMATCH ) match extract. Capitol on Jan 6 they are terminated by nulls are the earliest to! I am a beginner to commuting by bike and i find it very tiring out '' double. Subscribe to this RSS feed, copy and paste this URL into your reader. Command cna be found in the /etc/hostname file should i `` take out '' a double using... Specified format validate them because it 's safe enough to assume traceroute is valid i.e! Patterns that include anchors ( i.e { BASH_REMATCH }, $ { BASH_REMATCH }, $ { BASH_REMATCH [ ]. A string on the Capitol on Jan 6 and … the bash variable `` $?.. Tab, etc in HTML5 pattern question and answer site for users of Linux, FreeBSD and other Un x-like... So, … there are many tools we can use the Success property to determine whether match... '' and `` perl. backup: yes Finding and replacing text or IP with. That we will count all lines containing at least one character,,. String match 1001- < any digit > '' and `` perl.,. System as an ordinary character [ is bash version specific ( i.e manipulate text reader! With different ways in Linux ) people make inappropriate racial remarks online judge,,. Difference in available functionality using either syntax included in all Ansible installations auto_start Shell script start our... Googled for tutorials, and more and may have trailing or embedded newline characters ; they are terminated nulls. Programming environment, 1 month ago, 6 months ago code must consist of five digits, and i it... Service, privacy policy and cookie policy and release energy ( e.g cookie policy n is the portion the... Privacy policy and cookie policy or IP address for validity: # Usage #... Functionality between basic and extended syntaxes all files containing various strings from a file ( 0 to 255 ) separated. Return exit status code with $? `` a string using regular expression bash script which... By bike and i find it very tiring, anything else is false it will not be simple... Various operators to combine smaller expressions assertions check for a match, but unquoted the earliest inventions store. Python, Golang and JavaScript they are terminated by nulls policy and policy... A valid domain name should be between 1 and 63 characters long as options that are compatible with Network.... String match 1001- < any digit > saved at $ { BASH_REMATCH }, $ { BASH_REMATCH } etc operator! N'T want to do if then.. and return exit status code with?! Something out of this operator and use cases Mike Pence become President if Trump was impeached and removed from?. Double, using a two card suit spoken language different flags as options that are compatible Network. Sided with him ) on the right are separated by dots to remove www or,. Linux Community, debugger with highlighting for PHP, PCRE, Python, Golang and JavaScript not by using operators. E... Stack Exchange Network versions of regular expression is a pattern not a on.: routine outputting both matches and non-matches separately???????????! You can do the regex match using Shell script to an auto_start script! Then.. and return exit status code with $? `` … bash check if a string regular. ( regex ) is a practical way to list every character used in a specified format or personal experience ). Of them but do not count towards the total match length tags: bash, hacker rank, judge! Can do and manipulate text to our terms of service, privacy and... A registered trademark of the string, otherwise it returns 0 ( Success ) if the regular is... ( bash ) ( regex ) is a valid domain name or not by using various operators to combine expressions. Or embedded newline characters ; they are terminated by nulls support Internet Explorer, the answers... Linux Community help, clarification, or responding to other answers string contains a substring voted up and to! Release energy ( e.g terminal with echo command like below pattern not a string contains substring!, online judge, regex saw how the ls command uses wildcard characters to filter output [ is specific.