![]() This server is running the Linux kernel 5.16.5-arch1-1.Īs we can see, grep supports “ \d“, but we must use the right option. GNU grep supports the -P option to interpret PCRE patterns. Therefore, if we want the grep command to match PCRE, for instance, “ \d“, we should use the -P option: $ grep -P '\d' input.txt Otherwise, grep will search the literal ‘|’ character. \ (Back Slash) turn off the special meaning of the next character, as in \. Apart from use in command line tools like GNU grep, pcregrep and ripgrep, it is also used in programming languages for example Nim. PCRE is one of the most feature rich regular expression library. (Question) match expression at the end of a line, as in A. See pcre manual under topic Unicode character properties and regular-expressions: Unicode for more details. (Caret) match expression at the start of a line, as in A. ![]() ![]() Note that we shouldn’t escape the ‘|’ when we pass the -E option to grep. Here is a quick summary of the special characters used in the grep tool and their meaning: Text version. Let’s do the same test with the -E option: $ grep -E 'awesome|powerful' input.txt If there is more than one match, only the first occurrence of the match will be returned: Example. Grep allows us to use the -E option to interpret patterns as ERE. The search () function searches the string for a match, and returns a Match object if there is a match. For example, we can match a line containing either “ awesome” or “ powerful“: $ grep 'awesome\|powerful' input.txtĪs we’ve seen in the command above, we’ve escaped the ‘|’ character to give it special meaning. That is to say, if we don’t set an option, it only supports BRE syntax. Grep is by default in GNU BRE matching mode.
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