So what you can also do is pipe the data to tail command to just print only some of the last numbered lines. Likewise, a cat command with '-n' can also be used to print file content with line numbers. After learning five ways to count a number of lines, you must be wondering which is the best way for you?
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When you are searching for abc, grep will match all sorts of things, viz. You can compel the grep command to select only those lines that contain matches to form whole words those that match only abc word , as shown below:. The grep command has the ability to report the number of times a particular pattern has been matched for each file using the -c count option as shown below :.
In addition, users may use the '-n' option preceding each output line with the number of the line in the text file from which it was obtained as shown below :. Users may make use of the -v option to print inverts the match, which means it would match only those lines that do not contain the given word. For instance, print all lines that do not contain the word par by using the following command:. You must use the -l option to list file names whose contents mention a particular word, for instance, the word 'primary', using the following command:.
Lastly, you have the option to compel grep to display output in specific colors by using the following command:. There could be situations wherein you might want to search multiple patterns in a given file or set of files. In such scenarios, you should use the ' -e' command-line option that grep provides. For example, suppose you want to search for words "how", "to", and "forge" in all the text files present in your current working directory, then here's how you can do this:.
The ' -e' command-line option also helps in scenarios wherein the pattern begins with a hyphen -. For example, if you want to search for, say, "-how", then the following command won't be helpful:.
It's when you use the -e command-line option, the command understands what exactly you are trying to search in this case:. In case you want to limit the grep output to a particular number of lines, you can do that using the ' -m' command-line option.
For example, suppose you want to search for the word "how" in testfile1. But the requirement is for grep to stop searching after 3 lines containing the searched pattern have been found. So, to do this, you can run the following command:. So for example, if you have a bash script that has a loop, and you want to fetch one match per loop iteration, then using 'grep -m1' will do the needful.
If you want, you can also make the grep command obtain patterns from a file. The tool's -f command-line option lets you do this.
For example, suppose you want to search all the. Up until now, we have seen that by default grep matches and displays complete lines that contain search patterns. Improve this question. Add a comment. Active Oldest Votes. If you have already collected the grep output in a file, you could output a numbered list with: cat -n myfile If you only want the number of lines, simply do: wc -l myfile There is absolutely no reason to do: cat myfile wc -l Improve this answer. AdminBee Note that wc -l filename will output the filename in addition to the number of lines.
It's much easier to read, too. Chris, see unix. Show 3 more comments. The -c flag will do the job. Documented in the man page : -c, --count Suppress normal output; instead print a count of matching lines for each input file.
Is that the string you are trying to match or something else? The output shows the exact filenames that contain phoenix in the current directory but does not print the lines with the corresponding word:.
As a reminder, use the recursive search operator -r to include all subdirectories in your search. When grep prints results with many matches, it comes handy to see the line numbers. Append the -n operator to any grep command to show the line numbers. We will search for Phoenix in the current directory, show two lines before and after the matches along with their line numbers.
Individual files, such as log files, can contain many matches for grep search patterns. Limit the number of lines in the grep output by adding the -m option and a number to the command. In this case, the terminal prints the first two matches it finds in the sample file. If you do not specify a file and search all files in a directory, the output prints the first two results from every file along with the filename that contains the matches.
The grep command is highly flexible with many useful operators and options. By combining grep commands, you can get powerful results and find the text hiding in thousands of files. What is the grep Command? Was this article helpful? Goran Jevtic. Working with multiple departments and on various projects, he has developed an extraordinary understanding of cloud and virtualization technology trends and best practices.
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