Linux Fu: Named Pipe Dreams

If you use just about any modern command line, you probably understand the idea of pipes. Pipes are the ability to connect the output from one program to the input of another. For example, you can more easily review contents of a large directory on a Linux machine by connecting two simple commands using a pipe:

ls | less

This command runs ls and sends its output to the input of the less program. In Linux, both commands run at once and output from ls immediately appears as the input of less. From the user’s point of view it’s a single operation. In contrast, under regular old MSDOS, two steps would be necessary to run these commands:

ls > SOME_TEMP_FILE
less < SOME_TEMP_FILE

The big difference is that ls will run to completion, saving its output a file. Then the less command runs and reads the file. The result is the same, but the timing isn’t.

You may be wondering why I’m explaining such a simple concept. There’s another type of pipe that isn’t as often used: a named pipe. The normal pipes are attached to a pair of commands. However, a named pipe has a life of its own. Any number of processes can write to it and read from it. Learn the ways of named pipes will certainly up your Linux-Fu, so let’s jump in!

Continue reading “Linux Fu: Named Pipe Dreams”

Pipe Heating With An ATMega8

[Viktor] wanted a system to keep his pipes from freezing.  The common method of using heat tape works pretty well, but can be wasteful. Many people just turn it on for the entire winter. [Viktor] wanted to automate the heat tape’s power so that it only activated during times that the pipes could actually freeze. To do this, he rigged an ATMega8 to a temp probe and is using it to control an ATX power supply. Pretty slick [Viktor].

[via HackedGadgets]