![]() ![]() The search.txt file then includes both the file information and the text that has been found for sake of checking that you have what you want. Select-String -Path *.sas -Pattern "proc report" > c:\temp\search.txt It works well once you know what to do so here is an example: The input to the -Path switch can be a filename or a wildcard expression while that to the -Pattern can be a text string enclosed in quotes or a regular expression. While you can have the output appear on screen, it always seems easier to send it to a file for subsequent and that is what I am doing above. ![]() Usefully, this turns out to be the case but I found that the native functionality does not use what I have used before. Having made plenty of use of grep on the Linux/UNIX command and findstr on the legacy Windows command line, I wondered if PowerShell could be used to search the contents of files for a text string. PowerShell is closing the gap between Linux and Windows shell environments.Searching file contents using PowerShell 25th October 2018 The bottom line? Select-String is significantly faster than GNU grep on Windows Server 2008 R2. The total time to search the sample file is plotted on the y-axis in milliseconds. In the following graph, the number of lines in the sample files is plotted on the x-axis. The host operating system is Windows 2008 Server R2 SP1 with the latest hotfixes. ![]() The PowerShell equivilant of the grep command was: Select-String -Pattern “key” -Path. The command executed for grepping the file was: grep “key” “file1000.txt”įor PowerShell, I used version 3 (build. I used the latest GNU grep for Windows, version 4.2.1 released 2012-12/18. The time recorded was the average of the remaining five tests. The minimum time and the maximum time were dropped. The total milliseconds elapsed was used as the time measure. (You can download the resulting test files here: grep-select-string-test.zip).Įach search was performed seven times. There were eleven sample files: 1,000 sentences, 10,000 sentences, 20,000 sentences, and so on to 100,000 sentences. One in ten sentences contained the word “key” at a random location within the sentence. You have to pipe multiple commands together one command to transverse the directories, and one command to look for the pattern within each file found. Each file contained sentences of random length (5-25 random words). With the introduction of PowerShell, Windows has given us the grep functionality albeit with a much less finesse than the Linux equivalent. I generated sample files using a sample dictionary file. I do have the occassional free weekend and I was very curious. If Select-String was significantly slower, then a good weekend project might be to write a faster parser. Mark Boltz ( suggested running several tests of both and taking an average to get a sense of how Select-String stacks up. NET, we can make an assumption that grep should be faster than Select-String. Richard Minerich ( brought up a good point: compiled C code is generally faster than C# code. This had me wondering about how PowerShell’s Select-String stacks up. #2 trick: GNU grep is fast because it EXECUTES VERY FEW INSTRUCTIONS FOR EACH BYTE that it *does* look at.” “The key to making programs fast is to make them do practically nothing.” He also provided this excellent advice: “#1 trick: GNU grep is fast because it AVOIDS LOOKING AT EVERY INPUT BYTE. In the post titled “ why GNU grep is fast“, Mike described the algorithm grep uses. Mike was the original developer of GNU grep. Over the weekend, we were discussing on Twitter a post from Mike Haertel. ![]()
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