You can store a code snippet in a shell alias or a function, but when you type the alias or function name in a BASH shell and press 'Enter', the shell executes (or tries to execute) the snippet. That's no good if the snippet is incomplete or needs editing. A simple workaround is to paste the…

The file I'll be using for this demonstration is called demo and looks like this: demo is plain text with 2 tab-separated columns. The first column is sorted alphabetically, but the second column isn't sorted. What I want to find out is how many different letters are in the second column for each…

I worked on these bits of code to simplify a shell script of mine. You really wouldn't want to see the script's original commands here — they're way too ugly! The new commands are much prettier and work well. The problem To simplify the story, here's a comma-separated table called demo, sorted on t…

No, these aren't homework problems from a computer science class. They're interesting head-scratchers based on a data-analysis project I worked on recently, with the data 'reimagined' here for simplicity but with the underlying problems intact. We'll start with boys and girls, which are text files…

The complicated-looking script at the end of this article is in two parts. The first part detects the changes made when a data table is edited, and reports the changes as a plain-text logfile. It's a straightforward bit of shell scripting based on the diff command. The second part of the script…

In 2003 a strange paragraph made the rounds on email. It read: Aoccdrnig to rscheearch at an Elingsh uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, olny taht the frist and lsat ltteres are at the rghit pcleas. The rset can be a toatl mses and you can sitll raed it wouthit a…

In a 2014 Linux Rain article I describe a fast 'points plotter' for Google Earth. First I copy a list of latitude/longitudes (lat/lons) from a spreadsheet to the clipboard, then I launch a shell script with a keyboard shortcut. The script builds a KML file from the copied list and opens the KML for…

In this article I explain one way to group data items with AWK arrays. The code is a little mysterious but the results are impressive, especially in my second example! Case 1: Cricket stats The table 'runs' is tab-separated and lists the 86 national team cricket players who scored (or have so far…

There are two easy-to-use tools for generating numerical sequences. 'Brace expansion' is a BASH shell built-in, while the seq command is included in the GNU/Linux 'coreutils' package. Each tool has its peculiarities and advantages, as shown below. Simple sequences One difference between the two…

I often look something up in Wikipedia when reading non-browser documents, like PDFs, ODTs and emails. I wanted to have a little desktop window for those look-ups - somewhere I could check Wikipedia without opening a browser and without leaving the document I'm reading. This article describes how I…