TCP/UDP ports:
	Reason:  More than one server (software program) on an operating system
		Usually one operating system per piece of hardware
		Virtual machines do exist
	Some common ports
		22
		80 and 443
		3306
		Let's go look at Wikipedia
	nmap can do a thorough scan
		Or a brief scan

Did I fix the network demo?

Short list of commands still to come:
	sed
	cut (I've mentioned it)
	stuff related to compression, archives, and encryption
	Better to have a short list you remember!
		Feel free to learn others!
		Like curl (used with turnin)

Network tools:
	wget
	nc (netcat)
	nmap
	traceroute
	There are plenty more, but this is ok for now

fstab
	uuid and devices
	Partitions, extended and primary
	Numbering:  hd*, sd*, nvme

fdisk will show you
	cfdisk = Curses Fdisk

sshfs:  Mount a filesystem over SSH
	Userspace mounting
	fuse
	Connections are NOT automatically re-established
		- Could use a loop...

locate:
	This runs fast, because it consults a database
		- updatedb updates the database
find:
	This doesn't use a database
	Tests, example:  -type (b|c|d|f|l)
	Another example:  -name
	man has a list
	Logic operators!  -and, -or, -not, ( )
		- Remember, the shell will still expand stuff
	Actions:  -delete, -ls, -print (default), -quit
	Actions can be in logical operators!
		- lazy evaluation and actions
	xargs vs. backticks
		- xargs will do multiple batches
		- xargs can do multiple processors
		- -n option, for separate invocation

Archives!
	tar is a common unix archive
		- "tarballs"
		- tar command manipulates these (-cf to make, -xf to extract)
		- Meaning of -f, standard input
	Unix philosophy:  A toolbox
	Compression!
		- gzip
		- bzip2
		- xz (LZMA, like 7zip without 7zip 		
	You can compress files that aren't archives
		- Example:  zcat and logs
	tar can run the compression program for you!
		- tar -czf, -xzf, some people use -czvf and -xzvf
	
Backups often use tar
	- Example:  annelid (is only kind of backed up)
	- Distributed systems, and distributed backup
	- Two is one, and one is none
		+ When the zombies arrive...

cron again
	- At some point, I should really show you how to use this!
	- System administration:  /etc, cron has stuff in here
	- There's a way to do cron as a regular user, but I forgot how
		+ Why would you want this?

.zip archives:
	- These were popularized with WinZip, but they're not bad
	- zip tool, unzip tool
	- I use these more than .tar.gz
		+ Go with the flow

xargs example:  Download all CS228 assignments in parallel
	- Side note:  Web spider
	wget can already do this

Scripting:
	Scripts can be pretty elaborate!
	Example:  spectre-meltdown-checker.sh
	They can even have a GUI!
	cdrtoaster