Going back to the invention of the graphical user interface (GUI) in the 1970s, there has been tension between the advocates of the magical pointy-clickety GUI and the clickety-clackety command-line interface (CLI).
Part of it is stylistic… GUI’s are easier, faster, more productive.
Part of it is ego… CLI’s require more expertise and are endlessly customizable.
Given the evolutionary pressures on technology, the CLI should have gone extinct decades ago, as more and more expertise is packed into better and better GUI’s. And in fact, that has largely happened, but the persistence of the CLI can be explained by four persistent justifications…
- not yet supported in the GUI
- need to reproduce in the native OS
- automation and scripting
- I still drive stick-shift in my car, too
When your monitoring tool gets to the end of the information it can provide, it can be life-saving to be able to go to the UNIX/Linux command-line and get more information. Knowing how to interpret the output from CLI tools like “top”, “vmtstat”, and “netstat” can be the difference between waiting helplessly for deus ex machina or a flat-out miracle, and obtaining more information to connect the dots to a resolution.
Oftentimes, you have a ticket open with vendor support, and they can’t use screenshots from the GUI tool or report you’re using. Instead, they need information straight from the horse’s mouth, recognizable, trustworthy, and uninterpreted. In that case, knowing how to obtain OS information from tools like “ps”, “pmap”, and “ifconfig” can keep a support case moving smoothly toward resolution.
Likewise, the continued survival of CLI’s has a lot to do with custom scripting and automation. Sure, there are all kinds of formal APIs, but a significant portion of the IT world runs on impromptu and quickly-developed scripts based on shell scripts and other CLI’s.
Last, my car still has a manual transmission, and both my kids drive stick as well. There is no rational reason for this. We don’t believe we go faster or do anything better than automatic transmission. After almost 40 years behind the wheel, it can be argued that I’m too old to change, but that’s certainly not true of my kids. We just like being a part of the car.
Hopefully all of those reasons help explain why it is useful for Oracle DBAs to learn more about the UNIX/Linux command-line. You’re not always going to need it, but when you do, you’ll be glad you did.
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