You can also download this grep cheatsheet in PDF format, print it, and keep it at your desk to have a quick glance without losing time.The grep command is the very popular command used to filter string, text, and data in files and command outputs. You can bookmark this page for quickly referencing the grep command options and use cases. grep -a pattern binary_file Download Grep command cheat sheet You can make it search in binary files as if it was a text file using the -a option. You may use grep multiple times with pipe redirection for that. There is no specific option for the AND operator. You can use multiple patterns with the OR operator. However, you have to escape this special character in the following manner. If you want to see the lines that contain one pattern or the other, you can use the OR operator |. You can search for multiple patterns in the same grep search. grep -e regex_pattern file Search for this or that pattern There is a dedicated option -e that allows using regex pattern and option -E that allows using extended regex patterns. You can superpower your search by using a regex pattern.
This way, if you search for the word 'done,' it will only show lines containing 'done,' not 'doner' or 'abandoned'. To make grep search for full word only, you can use the option -w: grep -w search_string file If you are searching for the word 'done,' it will also show lines that contain the words 'doner' or 'abandoned.' Say you want to see which Markdown files contain the word "handbook," you can use: grep -l handbook *.md Search for full word onlyīy default, grep will show any lines that contain the given string.
If you have run the search on several files and you only want to see which files contain the string, you can use the -l option. grep -r search_pattern directory_path Display only the file namesīy default, grep shows the matching lines. It will search for the given pattern in all the files in the current directory and its subdirectories. You can perform a recursive search with grep option -r. sh), you could use: grep search_pattern *.sh Search for all the files in a directory recursively For example, if you want to look for a string in shell scripts only (files ending with. That could work, but a more practical example is to search into a particular type of files. You may provide more than one file to grep to search into. You can do the same with inverted search. To show the line numbers of the matching lines, you can use the -n option. You can of course, use the case-insensitive option -i. You can combine the -c and -v option to get the number of lines that do not match the given pattern. Instead of showing the matching lines, you can just get how many lines match the pattern with -c option. This 'invert matching' is used with the -v option: grep -v search_pattern filename You can use grep to display all the lines that DO NOT match the given pattern. grep -C 5 search_pattern filename Show the lines that do not match The command below will show 5 lines before the matching one, the matching line and 5 lines after the matching line. My favorite is the option -C because it shows lines that are before and after the matching ones. The command below will show 5 lines before the matching ones along with the matching line(s). Similarly, you can use the -B option to show lines before the matching ones. The command below will show the matching lines along with the 5 lines after the match. You can use the -A to show lines after the matching ones. But when you are troubleshooting something, it helps to see a couple of lines before and/or after the matching lines. Show lines before and after the matching linesīy default, you only see the matching lines. This way, grep will return lines that match both Holmes and holmes. You can ignore case matching with the -i option: grep -i search_pattern filename Case insensitive searchīy default, the search with grep is case-sensitive. Let's see a few common use cases of the grep command. You probably already know that to search for a particular text or pattern in a file, you have to use grep like this: grep search_pattern filename I have included a PDF cheatsheet which you can download, print and keep on your desk. It's good if you are already familiar with the grep command but you keep forgetting which option does what. I'll just the common options and their explanation here. Linux Handbook already has a detailed article on grep, so I won't go in depth here. This article lists the most common grep commands with quick examples. However, you'll end up using a handful of grep commands most of the time. You probably will never need or use all of them. The grep command has a huge number of options and use cases. It's especially helpful when you are troubleshooting or debugging. Grep is a powerful UNIX command that lets you search inside the file contents on a variety of parameters.
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