I am a huge believer in the Unix philosophy. Small, composable modules, loosely coupled. If you know your way around a Un*x system, you need little else. Here’s an example. I’ve got an NFS volume on a server and I wanted to backup (1) 
all the content to USB drives automatically, every hour. I decided to use the rsync program to do differential backups, but ran into an issue. My server is on a UPS, but the USB enclosure is not. So at times, after a power failure, the USB drives aren’t available and rsync (2)
tries to back everything to the /media folder by creating a new local folder instead of writing to the mounted USB drive. I figured I’d resolve this by checking that both my USB drives were mounted before I ran the rsync backup command. Here’s one solution: (3)
A few things to say here. First, I didn’t have to use a programming language. Bash shell script was sufficient. Second, notice how that variable x is assigned; I’m getting the output of the mount command, filtering the relevant drives, numbering them & finally extracting the (4)
last line as a count. This approach lets me combine many small command line programs and assign their composed output to a simple variable. Third, I can then use bash conditionals to determine what to do next. Last, rsync is an awesome CLI program that can do remote and (5)
local backups. This is just one of tons of super amazing, solid programs that come with most Un*x distros. A few lines of Bash and voila! Problem solved. And when it comes to automating execution, a single line in the cron scheduler runs the backup process every hour. (6)
And what’s more, you can do all this remotely from a phone, thanks to ssh. I love the flexibility & control Un*x provides. It’s a true testament to the Unix design philosophy that this operating system doesn’t just continue to be relevant, it literally runs the world. (End)
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