Keeping up with class:
	From here on, commands will sometimes be more complicated
	A lot of times, some minor point is missed
		Don't feel bad, happens all the time
	Then it causes a command to be not quite understood
		Which prevents learning whatever it was supposed to teach you
	Then it turns into a bigger problem
	So if a command doesn't make sense, ask me to explain it again

A couple things that will help you be fast:
	tab completion
	up arrow to cycle through old commands
	ctrl+r to search for old commands
		press it again to find the next result
		Enter if you find it

A general note on special characters:
	Shell processing may change them!

Command line grammar, example:

grep -i note /usr/share/dict/american-english

This will find all lines that contain the word "note" in either case inside the file /usr/share/dict/american-english

Pieces and what they are, using examples from above:
	grep :   The command to run
	-i : A flag, or option.  These set options to commands.
	note : A parameter, or argument.  Input to the command that is not a flag. 
		For grep, this is the thing to search for
	/usr/share/dict/american-english
		Another parameter.  For grep, this indicates the file to search

Commands typically work like this.

Spaces are separators!  Like in English
	Commands never contain a space
	Files usually do not
		- Some people like to put them in filenames
		- Programmers usually don't
	If you need an actual space in a filename, there are two options:
		- Use quotes, "bad filename"
		- Use \, the escape character, bad\ filename

Where to specify in the command line:
	Generally speaking, flags can be specified in any order
	Flags can usually be combined ( -i -r should be equivalent to -ir )
	Some flags may require a parameter (-o outfile)
		- In that case, the parameter must follow the flag
		- Sometimes, no space is required (-lpthread)
		- Sometimes, it is used (-l pthread)
	There are short and long options
		- Short:  -r -h
		- Long:  --recursive --help
		- Generally, long options have two dashes

Most commands include -h, -v, --help, or --verbose
	Not all, but it is very common

If commands have a mandetory parameter, they will usually print out usage info without it

Sometimes commands require that flags come before parameters
	Usually this is due to a variable number of parameters
	
A programming note:
	These appear as parameters to main in C/C++
		- Example with argc and argv
	In Python, you can import argv
	Generally, if you are writing a command-line tool, you should support flags
	There are libraries to help with that!
		- Example:  Python and argparse
		- For C:  getopt and argp

Homework 2, and the class of problems that grep solves
	
The source tree is at /usr/src/linux-source
	Let's find comments about Linus Torvalds
	How many files does he hold the copyright for?
	How many files have a space in the name?
	How many files are in the c language?
		- They'll end in .c
		- We need $
		- ^ is the other end

The dictionary is in /usr/share/dict
	What words have "note" in them?

Intro to expressions:  . means any character
	How many words are at least 10 letters long?
	How many words have at least two letters before two e's?
	How many have a z followed by two letters followed by a p?
		- Yes, this would be useful for scrabble
	
Isolating things:
	Let's get the ipv6 address from ifconfig with head and tail
		- The main weakness of this:  Length matters!
		- It'll be ok for homework 2
		- Feel free to use a better method if you like
	An expression with grep:
		- Regular expressions can handle this.  We'll learn a piece today
		- Demo anyway with .*
		- Generally, you can match most anything with these
		- Regular expressions take time and practice to master
		- There is more than one syntax for these

We learned these characters for grep:  . * ^ $
	Go ahead and remember these.
	Probably can solve the homework 2 without them, but they might help

At this point, see a command as an assembly line