![]() ![]() Note that even if you typed data as input to the first grep, you would only get any lines that contain 'word2' shown on the output.Īt one time, the answer used: grep -E 'word1.*word2|word2.*word1' 'word1.*word2' triggered the comments below.The (z. regular expression to search for both text1 and text2 strings. Now you have two processes running, the first grep and the shell, and they are both trying to read from the keyboard, and it is not determinate which one gets any given line of input (or any given EOF indication). E asks grep to use regex as a search string. With Heirloom Shell, the second grep completes and exits, and the shell prompts again. type f xarg grep -il osuser but i have one more string 'vsession' here i want to grep in which file these two strings are present. With Bash, the parent shell waits until all the processes in the pipeline have exited, so it sits around waiting for the grep -c to finish, which it won't do until you indicate EOF. 1 01-19-2011 gagan4599 Registered User 13, 0 Grep multiple strings in multiple files using single command Hi, I will use below command for grep single string ('osuser' is search string) ex: Code: find. c: Write only a count of selected lines to standard output. ![]() ![]() Note that the second grep doesn't read its standard input at all, so the pipe is superfluous. OPTIONS -E: Match using extended regular expressions. Or, in my case, it will fail since there's neither a file nor a directory called logs where I'm running the pipeline. The second grep does a recursive search for 'word2' in the files underneath directory logs (or, if it is a file, in the file logs). by typing Control-D), it will sit there, waiting for you to type something. 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. I know that there is a -o flag that can be used to get only matches. Grep allows you to search for multiple strings at once using the OR operator ( ). It finds matches correctly, but I can't figure out how to output all lines in a separate file, excluding matches within them. The first grep is going to count the number of occurrences of 'word1' on its standard input, and print that number on its standard output. I use the following command to search for such strings: grep -P ' (<>) A-Z0-9\.\s' File.txt.The initial script is: grep -c "word1" | grep -r "word2" logs If you run two commands, you should aim to select the less frequently occurring word in the first grep to minimize the amount of data processed by the second. Against that, the regex is more complex you might need to benchmark it to find out what's best - but only if performance really matters. However, if the file is huge and 'word1' occurs frequently, then you may be passing significant data down the pipe where a single command avoids that overhead. If the file is big but only a few lines contain 'word1', there isn't going to be much data passed on the pipe and using two command is fine. If the file is small, performance isn't likely to be an issue and running two commands is fine. as grep is doing, but > not using the strict full-string matching of. How much this matters depends on how big the data file is and how many lines match 'word1'. for multiple pattern as grep is doing for a single > pattern. The 'one command' variants have the advantage that there is only one process running, and so the lines containing 'word1' do not have to be passed via a pipe to the second process. If you know that 'word1' will precede 'word2' on the line, you don't even need the alternatives and regular grep would do: grep 'word1.*word2' logs You could use extended grep ( grep -E or egrep): grep -E 'word1.*word2|word2.*word1' logs However, it isn't necessary to use two commands like that. In this article, we’re going to show you how to exclude one or multiple words, patterns, or directories when searching with grep. The first grep finds lines with 'word1' from the file 'logs' and then feeds those into the second grep which looks for lines containing 'word2'. Posted 3 min read grep is a powerful command-line tool that is used to search one or more input files for lines that match a regular expression and writes each matching line to standard output. One simple rewrite of the command in the question is: grep "word1" logs | grep "word2" The grep method of multiple strings or patterns can be used if the operating system contains files with multiple strings and the user wants to target or reach. ![]()
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