Linux + C – Awk Example: Line Counter

Like most things, learning awk is much easier with examples. Today we'll look at a simple awk script which counts lines of code based on their type. The Code: linecount The following code uses a lot of regular expressions to determine the nature of a line. There are three formats for these if statements: if($0 ~ /REGEX/)

Linux + C – AWK for Beginners

Now that we know how valuable awk is, we can start to look at how we use it. The Three Phases There are three stages of an awk script: BEGIN - happens exactly once at the start of the program END - happens exactly once at the end of the program ...and the main loop We usually use the BEGIN

Linux + C – Your New Friend, Awk

In modern internet lingo, awk is a synonym for awkward or abnormal. However, the Linux tool awk (and its brethren, gawk and nawk) are anything but awkward. Awk - the programmable filter So far, we've looked at a set of filters that perform fairly singular tasks. LESS and MORE are designed to filter output to the

Linux + C – Some Useful Filters

Soon we'll talk about perhaps the most powerful programmable filter ever conceived (the scripting language AWK), but first let's look at a few other common filters and their uses. More The filter more is a program that lets us print output one screen at a time. If you've ever run a diff between two files or

Linux + C – Pipes and Filters

We've seen how to pass arguments to programs, and we've seen how to write to files. Now we'll look at how that is done from the Terminal. Pipes A pipe redirects the standard output (stdout) from one program to the standard input (stdin) of another. It acts like a tunnel (or pipe) between two programs, which