Hands-On System Programming with Linux

Word count

How many lines of source code are there in the C netcat.c source file I downloaded? (Here, we use a small part of the popular open source netcat utility code base.) We use the wc utility. Before we go further, what's wc? word count (wc) is a filter: it reads input from stdin, counts the number of lines, words, and characters in the input stream, and writes this result to its stdout. Further, as a convenience, one can pass filenames as parameters to it; passing the -l option switch has wc only print the number of lines:

$ wc -l src/netcat.c618 src/netcat.c$ 

Here, the input is a filename passed as a parameter to wc.

Interestingly, we should by now realize that if we do not pass it any parameters, wc would read its input from stdin, ...