If you're a Firefox user and you're a little fed up with going to Google Chrome every time in order to watch Netflix on your Linux machine, the good news is since Firefox 49 landed, HTML5 DRM (through the Google Widevine CDM (Content Decryption Manager) plugin) is now supported. Services that use…

When cleaning UTF-8 text files I sometimes come across invisible characters that I call 'gremlins'. These aren't the usual non-printing characters, like whitespace and (horizontal) tab, which are non-printing characters I expect to find in the plain text files I work with. Gremlins are weird things…

Recently I was checking for unmatched braces in a big text file with nearly half a million lines (300+ MB). Was there a closing brace for every opening brace? The text file was called 'beetle' and was actually a tab-separated table with each line divided into 77 fields. What I wanted to do was find…

Flags in AWK are variables which are set to either true or false. They're handy for defining ranges over which AWK can act, as shown below. The AWK used here is GNU AWK 4.1.1 (gawk 4). Sometimes flags aren't needed I'll demonstrate with a simple text file called demo, which has 6 lines with 3…

Lexical illusions are very hard to find when proofreading. The most common lexical illusion is a duplicated word, as in this well-known example: A lexical illusion: many people are not aware that the the brain will automatically ignore a second instance of the word 'the' when it starts a new line. …

Swapping the rows and columns in a table on the command line would seem to be a fairly easy thing to do. For example, with this tab-separated table (called 'tabbed') as input: get this tab-separated table ('swapped') as output: Datamash Transposing rows and columns is indeed easy if you have the…

Unless you've lived under a virtual rock since 2003, you have probably heard of Linden Lab's baby, Second Life at some point. The online virtual world, where you can literally pretty much do anything, might not be at the peak popularity it once experienced but there is still plenty going on. If…

Backreferences are part of the complicated and sometimes confusing world of regular expressions. The basic idea is this: you can substitute any part of a regular expression with a backslash followed by a number, so long as you surround the part to be substituted with round brackets. The command…

Most people store and organise their personal emails as individual files (messages) in folders. Those folders might be on a webmail company's servers, or in a mail client program on the user's personal computer. In both cases the emails are probably in a special email format. I'm horribly…

In this article I've pulled together some command-line tips for alternating lines of text. Questions about alternating lines turn up regularly on online help forums, and they sometimes get complicated answers. Here I've tried to keep things simple. Interleaving lines For demonstration purposes I'll…