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Grep for multiple strings8/30/2023 To change the pattern type, you may also use -G/ -basic-regexp (default), -F/ -fixed-strings, -E/ -extended-regexp, -P/ -perl-regexp, -f file, and other. Here's the basic syntax for searching for multiple strings with grep: grep 'string1string2string3' file. The OR operator tells grep to search for either of the specified strings. q/ -quiet/ -silent Do not output matched lines exit with status 0 when there is a match. Grep allows you to search for multiple strings at once using the OR operator ( ). threads Number of grep worker threads to use. When it finds a pattern that matches in more than one file, it prints the name of the file. l/ -files-with-matches/ -name-only Show only the names of files. The grep command can search for a string in groups of files. no-index Search files in the current directory that is not managed by Git. all-match When giving multiple pattern expressions, this flag is specified to limit the match to files that have lines to match all of them. You may also combine patterns with Boolean expressions such as -and, -or and -not. Here is the syntax using git grep with multiple patterns: git grep -all-match -no-index -l -e string1 -e string2 -e string3 file So - if you want to find multiple regexps or strings in a line or paragraph or file then don't use grep, use awk. How about across a whole file? Again can't be done in grep and trivial in awk (this time I'm using GNU awk for multi-char RS for conciseness but it's not much more code in any awk or you can pick a control-char you know won't be in the input for the RS to do the same): awk -v RS='^$' '/R1/ & /R2/' Now, what if you wanted to match 2 regexps in a paragraph rather than a line? Can't be done in grep, trivial in awk: awk -v RS='' '/R1/ & /R2/' Which again are poor choices whereas with awk you simply use a string operator instead of regexp operator: awk 'index($0,S1) & index($0.S2)' Then pop open your 'results' (or whatever) file and you'll have all your responses. Or again use 2 greps and a pipe: grep -F 'S1' file | grep -F 'S2' I haven't had to grep multiple strings like that, but perhaps grepping the first, routing it to a file, grepping the second, appending the file, and grepping the third, appending to the same file. Now, what if you actually wanted to match literal strings S1 and S2 instead of regexps R1 and R2? You simply can't do that in one call to grep, you have to either write code to escape all RE metachars before calling grep: S1=$(sed 's///g s/\^/\\^/g' <<< 'R1') While in awk it'd be the concise, obvious, simple, efficient: awk '/R1/ & /R2/ & /R3/' Putting that aside, what if you wanted to extend your solution to match 3 regexps R1, R2, and R3. You'd have to use 2 greps and a pipe for that: $ echo 'theatre' | grep 'the' | grep 'heat'Īnd of course if you had actually required them to be separate you can always write in awk the same regexp as you used in grep and there are alternative awk solutions that don't involve repeating the regexps in every possible sequence. Lets say you want to find lines that contain the and heat: $ echo 'theatre' | grep 'the.*heat|heat.*the' To match 2 regexps R1 and R2 in grep you'd think it would be: grep 'R1.*R2|R2.*R1'īut what if R2 overlaps with or is a subset of R1? That grep command simply would not work while the awk command would. Terminal displays only the final results of the two commands combined.Don't try to use grep for this, use awk instead. The first part of the command looks for the word Walden in any files in the current directory, and the second runs another grep command on the results of the first command. You’d use this command: grep Walden * | grep Pond. Say you want to find files containing both Walden and Pondon the same line. Using the pipe ( |), a Unix redirection operator, you can tell grep to search for more than one string. (Note that you can also combine options-for instance, grep -rl Walden searches subfolders and returns only a list of files containing the word Walden. Get started with the helpful options listed here. The grep command has several options that let you fine-tune the way you search for text, as well as the kind of results grep returns. Returns the names of files containing Walden and the number of hits in each file. Finds Walden in any file in any subfolder of ~/Documents.įinds only live does not find liver, lives, lived, and so on.įinds files containing Walden, but returns only a list of file names.
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