-L, -files-without-match: Prints the file name that does not contain the provided matching pattern.-l, -files-with-matches: Prints the file name that contains the provided matching pattern.We can use the following flags to separate files that contain the matching pattern: We can also use grep to narrow down the files that contain a matching pattern.
Grep examples line number how to#
Until now we had discussed how to search for matching patterns in a file or input string.
Tip: The -c flag can be very useful if you have to count the number of times an error message appeared in a log file. The word "fruit" appears 3 times in the file. This is how the -c flag works: grep -c "fruit" fruits.txt We can count the number of times the matched string appears in the file. How to Count the Number of Occurrences of the Provided Pattern using -c This would include occurrences like "grape fruit", "dragon fruit" and so on like this:īut, if we only want "fruit" in our results, we can use the -w flag like this: grep -w "fruit" fruits.txtĭo you see the difference? The latter result returned only one line where the exact word "fruit" was found. If we grep "fruit" without any flags, it would return any occurrence of the word "fruit". If you were to match an exact word rather than just the occurrence of a pattern, you can do so by using the -w flag. How to Find the Exact Matching Word from the Input File or String using -w For that, we can supply the -n flag to grep like this: grep -n "berries" fruits.txtįrom the output, we can see that the word "berries" occurs on line #5 of the file. There are times when we want to get the line numbers against the matching string. How to Find the Line Numbers Against Matching Input using -n The output returned all the lines that do not contain "berries". Let's say, if we want to get all the lines that do not contain the word "berries", the command would look like this: grep -v "berries" fruits.txt We can reverse the results of the grep command to include non-matching results. Output: How to Select the Non-Matching Lines using -v
It should match all occurrences of "berries" regardless of their case. Let's find the word "berries" from our sample file. We can command grep to return results while ignoring the case of the matching string. Here's the output: How to Ignore Case Distinctions using -i If we want to find the string "fruit" in the file fruits.txt, we can do so like this: grep "fruit" fruits.txt Contents of fruits.txt How to Find a Matching String with grep Melons – watermelons, rockmelons and honeydew melons Tropical and exotic – bananas and mangoesīerries – strawBERRIES, raspberries, blueberries, kiwifruit and passionfruit Stone fruit – nectarines, apricots, peaches and plums In the coming examples, we will use the file fruits.txt with the following content: apples and pearsĬitrus – oranges, grapefruits, mandarins and limes
-i, -ignore-case: Ignores case distinctions in patterns and input data.In this article, we will discuss the following options that can be used with grep: It is a good practice to close the PATTERN in quotes when grep is used in a shell command. Grep finds each line that matched the provided PATTERN. In the above syntax, grep searches for PATTERNS in each FILE. The syntax of the grep command is as follows: grep PATTERNS Grep syntax In this article, we will discuss the grep command's syntax and its usage with some examples.
Grep examples line number code#
If you are a system admin who needs to scrape through log files or a developer trying to find certain occurrences in the code file, then grep is a powerful command to use. grep is short for "global regular expression print". Grep is a useful command to search for matching patterns in a file.
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