How can I write a case statement using regex as condition (to match numbers)? Is this possible and if so what is the proper syntax when using regex for the pattern to match? 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! I looked at previous posts but there are not like my case. Because this gets tiresome very quickly, the egrep command was created. 3)Extended Regular expressions (Use option -E for grep and … It is the most popular editor amongst Linux Journal readers. You can convert the case of the string more easily by using the new feature of Bash 4. (patterns) (regex)? Basically regular expressions are divided in to 3 types for better understanding. Case command pattern supports regular expressions, which provide a concise and flexible means for identifying words, or patterns of characters. I keep finding conflicting information regarding the ability to use regex in a bash case statement. Pattern matching in a bash case statement using regex. Introduction – In bash, we can check if a string begins with some value using regex comparison operator =~. Thanks. This post for example shows how to make regex case insensitive when using list of characters []. Think of it terms of regular expressions: Glob Regular Expression Equivalent Description? Bash Case Example 3. The egrep command is the same as the grep -E combination, you just don’t have to use the -E option every time. (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. It enable you to match several values against one variable. Like in the following example, valid numbers are falling through the numeric regex that's intended to … The case statement is good alternative to multilevel if-then-else-fi statement. Solution # 2: Use regex with case patterns. Last edited by radoulov; 04-28-2014 at 04:10 PM .. The bash man page refers to glob patterns simply as "Pattern Matching". Bash case regex output. It is easier to read and write. bash case regex, Is there any way other than putting the two character cases [Ss] for each character because it is not about the initials, but all the characters can come in any case? ← Exit command • Home • Dealing with case sensitive pattern →. I tried a few different ways I came up with (e.g., [0-9]+ or ^[0-9][0-9]*$ ); none of them works. Also, refer to our earlier article on Bash ~ expansaion and { } expansion. To use the extended regular expressions with grep, you have to use the -E (extended) option. I've been using the following regex below in a bash script on RHEL 5.5 using version GNU bash, version 3.2.25(1)-release I've tried using the script on RHEL 6.3 which uses GNU bash, version 4.1.2(1)-release I assume there's been alot of changes to bash since that's quite a jump in revisions.... (12 Replies) ‘^’ symbol is used to convert the first character of any string to uppercase and ‘^^’ symbol is used to convert the whole string to the uppercase. Regular expressions (Regexp) is one of the advanced concept we require to write efficient shell scripts and for effective system administration. One can test that a bash variable starts with a string or character in bash efficiently using any one of the following methods. 1)Basic Regular expressions. After deleting the lines matches with the pattern Vim: $ ./fileop.sh -d Vim text It is the most popular editor amongst Linux Journal readers. ... How to check if a string begins with some value in bash. 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