![]() ![]() But let's imagine we got a much longer list than we could easily count. It looks like we had four security-related articles last month. The format we used was grep, followed by the -i flag (which tells grep not to be case sensitive), followed by the pattern we wanted to search for, and then the file in which we were searching. ,Article,Daniel J Walsh,50 ways to avoid getting hacked in 2017,14,/article/17/1/yearbook-50-ways-avoid-getting-hacked,"Yearbook, 2016 Open Source Yearbook, Security and encryption, Containers, Docker, Linux",2143 ,Article,Alan Smithee,Data Privacy Day 2017: Solutions for everyday privacy,5,/article/17/1/every-day-privacy,"Big data, Security and encryption",1424 ,Article,Subhashish Panigrahi,How communities in India support privacy and software freedom,0,/article/17/1/how-communities-india-support-privacy-software-freedom,Security and encryption,453 ,Article,Tiberius Hefflin,4 ways to improve your security online right now,3,/article/17/1/4-ways-improve-your-online-security,Security and encryption,1242 But for now, let's just search for a simple string. grep is an incredibly powerful tool, thanks to the regular expressions you can build to match very precise patterns. ![]() With grep, you can search a file or other input for a particular pattern of characters. Okay, now let's ask ourselves: Out of these 92 articles, how many of them were about a security topic? For our purposes, let's say we're interested in articles that mention security anywhere in the entry, whether in the title, the list of tags, or somewhere else. 93 lines in this file since we know the first row contained headers, we can surmise that this is a list of 92 articles. $ wc -l jan2017articles.csvĪnd, there it is. In our case, we want to know the number of lines. Short for "word count," wc can count the number of bytes, characters, words, or lines in the file. That's great, but how big is this file? Are we talking about dozens of articles we want to analyze, or hundreds, or even thousands? The wc command can help with that. Looks like we've got a list of articles with the date they were published, the type of content for each one, the author, title, number of comments, relative URL, the tags each article has, and the word count. ![]() Post date,Content type,Author,Title,Comment count,Path,Tags,Word count Let's look at the top of the file and see if it has headers to explain what each column means: $ head -n 1 jan2017articles.csv Looking at those last three lines, I can pick out a date, author name, title, and a few other pieces of information immediately. ,Poll,Jason Baker,What is your open source New Year's resolution?,1,/poll/17/1/what-your-open-source-new-years-resolution,186 ,Article,Jen Wike Huger,The preview for January,0,/article/17/1/editorial-preview-january,358 ,Article,Scott Nesbitt,3 tips for effectively using wikis for documentation,1,/article/17/1/tips-using-wiki-documentation,"Documentation, Wiki",710 If you don't specify the number of lines you want to see, you'll get 10. Both are utilities for showing a specified number of lines from the top or bottom of the file. What's in it? What does its format look like? You can use the cat command to display a file in the terminal, but that's not going to do us much good if you're working with files more than a few dozen lines.Įnter head and tail. So let's try out a few of the many simple open source tools for data analysis and see how they work! If you'd like to follow along with these examples, go ahead and download this sample data file, from GitHub, which is a CSV (comma separated value) list of articles we published to in January.įirst, let's get started by getting a handle on the file. Free online course: RHEL Technical Overview.extension AVAudioPCMBuffer ĪudioBuffer.mData?.copyMemory(from: addr, byteCount: Int(audioBuffer. Here are functions that can do conversion between NSData and AVAudioPCMBuffer. Buffer length is frameCapacity * bytesPerFrame. ![]()
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