bash regex does not match

I realize you said “read the bash man pages” but at first, I thought you meant read the man pages within bash. What I'm saying is, you posted a relatively large block of code. ("My code doesn't work" isn't a good StackOverflow question. If file does not exist, match exits 67, or whatever code was specified by -x. from a metacharacter into a literal, you have to escape it. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. How to get the source directory of a Bash script from within the script itself? Making statements based on opinion; back them up with references or personal experience. Also note that _ doesn't need to be escaped, you can write _ instead of \_. So, now you just need to figure out the other problems with your regex. Join Date: Nov 2008. Thanks for contributing an answer to Stack Overflow! Anchor symbols drop out all matched text if it’s not located at a boundary. message='123456789' echo "${message//./*}" displays 123456789? But it always says that your regex didn't match but the regex tool shows that it matches with my regular explanation. It is inconceivable that you, Regex doesn't match with the lines in txt file, Podcast 302: Programming in PowerPoint can teach you a few things. First atomic-powered transportation in science fiction and the details? I'd like to be able to match based on whether it has one or more of those strings -- or possibly all. How do I tell if a regular file does not exist in Bash? Surely you can play around and figure out which part is the problem?). To learn more, see our tips on writing great answers. If I put regex="AAA \(bbb .+\) CCC" it works but it doesn't meet my requirement to match digits only. Making statements based on opinion; back them up with references or personal experience. your coworkers to find and share information. message='123456789' echo "${message//[0-9]/*}" display ***** but. How can I check if a directory exists in a Bash shell script? RegEx match open tags except XHTML self-contained tags, How to concatenate string variables in Bash, White neutral wire wirenutted to black hot. The problem was about bash configuration, i think it is not a question like 'my code isn't work'. There is no need to escape hyphens. C++20 behaviour breaking existing code with equality operator? All the documentation I've seen says that . stackoverflow, why does BASH_REMATCH not work for quoted regex. So, what does your original pattern actually accomplish? Okay. Pattern matching results. You could use a look-ahead assertion: (? RegEx match open tags except XHTML self-contained tags, Find and kill a process in one line using bash and regex, Negative matching using grep (match lines that do not contain foo), Check whether a string matches a regex in JS, Read a file line by line assigning the value to a variable. 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! Use [0-9] instead: Thanks for contributing an answer to Stack Overflow! I'm trying to match some lines against regex that contains digits. But if you happen not to have a regular expression implementation with this feature (see Comparison of Regular Expression Flavors), you probably have to build a regular expression with the basic features on your own. Likewise, we changed the second regular expression from .+ to \w+ , which does the same thing. I'm reading the lines from a text file and check if it matches with the regex that I've created or not. In a bash script, why does. The bash man page refers to glob patterns simply as "Pattern Matching". Either use standard character set or POSIX-compliant notation: As read in Finding only numbers at the beginning of a filename with regex: \d and \w don't work in POSIX regular expressions, you could use [:digit:] though. How do airplanes maintain separation over large bodies of water? Enforcing regex validated user input - what is wrong in this bash script? The text ⌜minus⌟ matches nominus and minuses.But ⌜minus\b⌟ will not find minuses.If you search for exact word only, you may use ⌜\bminus\b⌟, this will ensure that each match will be connected with word’s start and end in the same time.. If statement with a regex in bash not working, Current code marking REGEX as invalid even though it is valid via REGEX checkers. stackoverflow, regex matching in a Bash if statement . Why does this imply that I get a match only if the search string is exactly 'a'? Did I make a mistake in being too honest in the PhD interview? Wrong. But this returns 0 [[ "abc def .d,x--" == a[abc]*\ \.d,x* ]]; echo $? wikipedia, POSIX extended regular expression. An expression is a string of characters. Stating a regex in terms of what you don't want to match is a bit harder. fly wheels)? It stands for a dot.? Regular expression to match a line that doesn't contain a word. is a wildcard that matches any single characters (it does not mean that the previous character is optional). However, if I enter that same syntax into grep on the command line, I get an unexpected result: Automate the boring stuff with Python states: To indicate that the entire string must match the regex, that is, it’s not enough for a match to be made on some subset of the string, use the ^ and $ together. Given a list of strings (words or other characters), only return the strings that do not match. Text alignment error in table with figure. Join Stack Overflow to learn, share knowledge, and build your career. – anubhava Feb 15 '17 at 15:22 Hmmm, never mind, I got confused: it's grep that doesn't handle + (at least not without additional options). riptutorial, BASH_REMATCH. Could all participants of the recent Capitol invasion be charged over the death of Officer Brian D. Sicknick? site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. (Photo Included), Don't understand the current direction in a flyback diode circuit. Can this equation be solved with whole numbers? Moderator. How to find out if a preprint has been already published, Relative priority of tasks with equal priority in a Kanban System, CSS animation triggered through JS only plays every other click, Where is this place? Join Stack Overflow to learn, share knowledge, and build your career. Those characters having an interpretation above and beyond their literal meaning are called metacharacters.A quote symbol, for example, may denote speech by a person, ditto, or a meta-meaning [1] for the symbols that follow. How do you access the matched groups in a JavaScript regular expression? Do rockets leave launch pad at full thrust? Posts: 12,296 Thanks Given: 679. Bash pattern matching Results, Types and Tools will be covered. Match dates (M/D/YY, M/D/YYY, MM/DD/YY, MM/DD/YYYY) Cheat Sheet. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. What Constellation Is This? Should I "take out" a double, using a two card suit? How do I tell if a regular file does not exist in Bash? (*.jpg|a.jpg) should not match, because a.jpg matched both patterns, and the ? I tried escaping the { and } as well, but didn't get the 0 return status I was expecting. I am trying to write a bash script that contains a function so when given a .tar, .tar.bz2, .tar.gz etc. Text alignment error in table with figure, Plotting datapoints found in data given in a .txt file. shell scripts. Is there a mod that can prevent players from having a specific item in their inventory? What are the earliest inventions to store and release energy (e.g. How can I count all the lines of code in a directory recursively? Comments. 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 ? Stack Overflow for Teams is a private, secure spot for you and Then, in the first regex, we replaced . Last Activity: 1 January 2021, 1:47 AM EST. !999)\d{3} This example matches three digits other than 999. [0-9]+ worked for me on older BASH 3.2 as well so not sure why Ubuntu BASH is not liking it. How can I convert a regular expression to work in a Bash script? Character classes . Asking for help, clarification, or responding to other answers. This operator matches the string that comes before it against the regex pattern that follows it. A Brief Introduction to Regular Expressions. # sh bashre.sh 'aa(b{2,3}[xyz])cc' aabbxcc aabbcc regex: aa(b{2,3}[xyz])cc aabbxcc matches capture[1]: bbx aabbcc does not match Mitch Frazier is an embedded systems programmer at Emerson Electric Co. Mitch has been a contributor to and a friend of Linux Journal since the early 2000s. Can index also move the stock? Tags. So far, so good. Linux bash provides a lot of commands and features for Regular Expressions or regex. Unix & Linux: bash regex does not recognize all groupsHelpful? Slicing a bar in three pieces - probability. Match everything except for specified strings . * mksh does not support POSIX character classes. Asking for help, clarification, or responding to other answers. {1,} with [a-zA-Z0-9]{1,} which will now not match the "yahoo.com.yahoo.com" because the periods do not match the character set. Cool. At any rate, man bash returns a huge file, which is 4139 lines (72 pages) long. How to validate an email address using a regular expression? Bash Regex to check if first character of string is a number, How to find a number in text at specific location using regex in java, How to validate an email address in JavaScript. How can I check if a program exists from a Bash script? Why does Steven Pinker say that “can’t” + “any” is just as much of a double-negative as “can’t” + “no” is in “I can’t get no/any satisfaction”? Using BASH =~ regex to match multiple strings. I'm sure this is simple, I just can't get my brain around it. Location: Amsterdam. Therefore, character ranges like [0-9] are somewhat more portable than an equivalent POSIX class like [:digit:]. is "zero or one", right? The tutorial says that to turn the . Types of patterns. My problem is understanding the logic. When the string matches the pattern, [[ returns with an exit code of 0 ("true"). How can I keep improving after my first 30km ride? What are the key ideas behind a good bassline? your coworkers to find and share information. ... For example, it appeared to me that, given a.jpg, the pattern ? Why does this regex not match anything? Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star? so putting /9\.00/g into the online regex box will only match 9.00, as expected, not 9-00 nor 9500. Generally, Stocks move the index. 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. Can 1 kilogram of radioactive material with half life of 5 years just decay in the next minute? matches any character in regex, even in bash, but it's not working for me. Stack Overflow for Teams is a private, secure spot for you and For each argument string, match stops when it hits the first matching line of the file. rev 2021.1.8.38287, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide, At least with bash 4.3.11 (the one that comes with Ubuntu 14.04), Finding only numbers at the beginning of a filename with regex, Podcast 302: Programming in PowerPoint can teach you a few things. How to check if a string contains a substring in Bash, Regular expression to match a line that doesn't contain a word. Remove the leading /, none of your lines begin with it. 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 ? file it uses tar with the relevant switches to decompress the file.. Why does Steven Pinker say that “can’t” + “any” is just as much of a double-negative as “can’t” + “no” is in “I can’t get no/any satisfaction”? so your expression should be one of these: All together, your script can be like this: Digit notation \d doesn't work with your bash version. In the case of an empty list, the pattern did not match. One easy way to exclude text from a match is negative lookbehind: w+b(?