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Fix small typo

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Joshua Boniface 2017-03-21 15:39:13 -04:00
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content/post/a-raspberry-pi-bmc.md
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@ -75,7 +75,7 @@ To keep everything neat, I used a through-hole solderable breadboard to mount al
The software side started out as a basic Raspbian system, however I wanted to make it a little more "BMC-like", in a sense stripped-down and easy-to-use with a small set of commands. I started by writing a simple "shell" emulator in BASH, and using a constant loop and hostname prompt along with `stty` to keep it focused and running. Each command triggers a function which performs its specific job and then returns to the "shell". While `bash` is available also, it should rarely be needed. The software side started out as a basic Raspbian system, however I wanted to make it a little more "BMC-like", in a sense stripped-down and easy-to-use with a small set of commands. I started by writing a simple "shell" emulator in BASH, and using a constant loop and hostname prompt along with `stty` to keep it focused and running. Each command triggers a function which performs its specific job and then returns to the "shell". While `bash` is available also, it should rarely be needed.
The actual software doing the heavy lifting is a combination of `screen`, to view the host system serial console, and the `gpio` utility by WiringPi (Debian package `wiringpi`). The `screen` session is configured to start automatically at BMC boot to ensure all serial output is captured and stored for later analysis - a major problem with the (few) SSH-based BMCs I've tried! The `gpio` program makes writing and reading the GPIO pins simple and easy, returning 0 or 1 for the low/high states and easily writing states. By writing the BMB shell in `bash`, I was able to get all the flexibility I wanted without any programming overhead; the whole thing is under 200 lines. The actual software doing the heavy lifting is a combination of `screen`, to view the host system serial console, and the `gpio` utility by WiringPi (Debian package `wiringpi`). The `screen` session is configured to start automatically at BMC boot to ensure all serial output is captured and stored for later analysis - a major problem with the (few) SSH-based BMCs I've tried! The `gpio` program makes writing and reading the GPIO pins simple and easy, returning 0 or 1 for the low/high states and easily writing states. By writing the shell in `bash`, I was able to get all the flexibility I wanted without any programming overhead; the whole thing is under 200 lines.
(Pictured: an example session with `bmc.sh`) (Pictured: an example session with `bmc.sh`)