Initial commit.

4 files changed, 332 insertions, 0 deletions

diff --git a/topics/boot.txt b/topics/boot.txt
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+++ b/topics/boot.txt
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+BIOS
+	firmware image on ROM chip
+		ROM is either a dual in-line package or plastic leaded chip carrier
+	POST
+	initializes HW, e.g. memory, video card, keyboard, USB hosts
+	finds a bootable device (HDD, ODD, USB flash drive, etc.)
+	reads MBR and executes stage 1 boot loader
+boot loader, e.g. GNU GRUB
+	may offer user OS list and/or some other interactive IX (e.g. CLI)
+	will load a kernel, e.g. Linux, into memory and begin its execution
+Linux
+	initializes memory, interrupts, etc.
+	may mount initial ramdisk
+	loads and schedules init and kernel threads
+initial ramdisk
+	finds root filesystem
+	loads required drivers and runs required utilities to mount root fs
+		e.g. for RAID, LVM2, ext4
+	checks for a suspend-to-disk virtual memory image and resumes if found
+	look at initrd on Debian:
+		$ gunzip -c /boot/initrd.img-`uname -r` | cpio --extract
+		warning: will extract to current working directory
+init
+	multiple implementations
+		GNU/Linux:
+			System V-style init
+			systemd
+			Upstart
+			runit
+			OpenRC
+			Initng
+		BSDs:
+			own lightweight and modular daemon
+		BusyBox/Linux:
+			own lightweight daemon
+	SysV-style:
+		runlevels
+			0 - halt
+			1 - single-user mode
+			2-5 - multi-user mode
+			6 reboot
+		reads /etc/inittab
+			default runlevel
+			actions of runlevels
+			Ctrl+Alt+Del behavior
+			programs to control TTYs (e.g. /sbin/getty)
+			etc.
+		runs initialization scripts
+			`/etc/rcN.d/* start`, where N = runlevel
+			links to /etc/init.d/*
+			cron, servers, ACPI daemon, Network Manager, DMs, etc.
+getty
+	prints /etc/issue, unless disabled
+	prompts for username
+	calls /bin/login
+login
+	prompts for password
+	loads user environment
+	starts user's default shell (e.g. /bin/bash)
+display manager
+	starts X.org server
+	prompts for user name and password
+	starts window manager and desktop shell
diff --git a/topics/shell-tut.txt b/topics/shell-tut.txt
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index 0000000..0a73cb0
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+++ b/topics/shell-tut.txt
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+first steps and basic output
+	how shell reads input - three methods
+	use of "echo" built-in utility
+	ex: hello world
+simple commands, field splitting, and quoting
+	ex: maybe cd, mkdir/touch, etc.
+tilde and pathname expansion
+	ex: cd with tildes
+	ex: cd/mkdir/touch with pathname expansions
+parameters
+	defining variables and expanding their values
+	positional parameters, special parameters, and shell variables
+	ex: assign variables
+	ex: expand and print variables and positional parameters
+command substitution
+	ex: commands in subshells, output assigned to variables
+arithmetic expansion
+	ex: some expressions, assignments, etc.
+shell commands
+	revisit simple commands
+	command search and execution
+	pipelines
+	lists
+		sequential
+		asynchronous
+		AND
+		OR
+	compound commands
+		grouping
+			subshell vs current shell, shell execution environment:
+				open files
+				working directory
+				shell parameters
+				shell functions
+				shell options
+				shell aliases
+		if
+			show "test"/"[" command
+		while
+			ex: loop over positional parameters
+				#! /bin/sh
+				while [ $# -gt 0 ]; do
+					printf '%s\n' "$1"
+					shift
+				done
+			ex: read from input
+		until
+		for
+		case
+	functions
+exit status
+I/O redirection
+built-in utilities
+	colon
+	export
+	break [n]
+	continue [n]
+	dot
+	eval
+	exec
+	exit
+	export
+	return
+	set
+	shift
+	unset
+utilities
+	cat
+	cd
+	chgrp
+	chmod
+	chown
+	cp
+	date
+	dd
+	df
+	diff
+	dirname
+	du
+	echo
+	expr
+	false
+	file
+	fold
+	getopts
+	grep
+	head
+	id
+	kill
+	ln
+	lp
+	ls
+	mailx
+	mesg
+	mkdir
+	mkfifo
+	more
+	mv
+	nice
+	pr
+	printf
+	ps
+	pwd
+	read
+	rm
+	rmdir
+	sed
+	sh
+	sleep
+	sort
+	stty
+	tail
+	test
+	time
+	touch
+	tr
+	true
+	uniq
+	wc
+	who
+
+example scripts:
+	screen-batt
+	/usr/local/lib/pjrand.sh and /usr/local/bin/screensaver
+	/bin/which of Debian (ex. of IFS)
+	changelog-gen
diff --git a/topics/shell.txt b/topics/shell.txt
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+++ b/topics/shell.txt
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+introduce the shell interpreter
+	POSIX.1-2008 XCU 2.1
+	shell reads input from:
+		a specified file,
+		'-c' option argument, or
+		stdin (interactive mode)
+	shell splits input lines into tokens and parses them
+	shell expands words
+	shell performs I/O redirection
+	shell executes functions, built-in commands, files, etc.
+parameters and variables
+	positional parameters
+		POSIX.1-2008 XCU 2.5.1
+		decimal numbers greater than 0, e.g. $1 and $2
+		multiple-digit numbers should be enclosed in braces
+		assigned with:
+			shell arguments when shell starts
+			function arguments when a function is called
+		can be reassigned using 'set' built-in command
+	special parameters
+		POSIX.1-2008 XCU 2.5.2
+		@
+			all positional parameters
+		*
+			all positional parameters
+		#
+			number of positional parameters
+		?
+			exit status of most recent command pipeline
+		-
+			current option flags
+		$
+			process ID of shell
+		!
+			process ID of most recent background command
+		0
+			name of shell or shell script
+	shell variables
+		POSIX.1-2008 XCU 2.5.3
+		HOME
+			pathname of user's home directory
+		IFS
+			delimiters for field splitting
+			default: <space> <tab> <newline>
+		LINENO
+			line number of current script, if any
+		PATH
+			list of paths which should be searched for commands
+		PS1
+			prompt value to be expanded and written to standard error
+			default value: "$ "
+		PWD
+			absolute pathname of the current working directory
+word expansions
+	tilde expansion
+		POSIX.1-2008 XCU 2.6.1
+		tilde-prefix: unquoted tilde at the beginning of a word
+			followed by all unquoted characters until first unquoted slash
+		login name is all characters in tilde-prefix following tilde
+		if login name is empty (tilde-prefix == "~")
+			expanded to value of HOME
+		else
+			expanded to home directory associated with login name
+	parameter expansion
+		POSIX.1-2008 XCU 2.6.2
+		${expression} or $expression
+		expression:
+			parameter
+			parameter:-word
+			parameter:=word
+			parameter:?word or parameter:?
+			parameter:+word
+			#parameter
+			parameter%word
+			parameter%%word
+			parameter#word
+			parameter##word
+	command substitution
+		POSIX.1-2008 XCU 2.6.3
+		$(command)
+		or
+		`command`
+		expanding:
+			shell executes command in a subshell
+			shell replaces substitution with stdout of the command
+			newlines within command are allowed
+		nesting
+			`command1 \`command2 foo\` bar`
+			$(command1 $(command2 foo) bar)
+	arithmetic expansion
+		POSIX.1-2008 XCU 2.6.4
+		$((expression))
+		expanding:
+			shell processes expression
+			shell replaces substitution with value of the expression
+		arithmetic:
+			signed long integer precision
+			decimal, octal, and hexadecimal constants
+				e.g. 42, 052, 0x2A
+			operators:
+				( ), unary +, unary -, +, -, *, /, %
+				~, !, <<, >>, &, ^, |
+				<, <=, >, >= ==, !=, &&, ||, expr ? expr : expr
+				=, +=, -=, *=, /=, %=, <<=, >>=, &= ^=, |=
+			shell variables
+				if x has an integer value, then the following are equivalent:
+				$((x + 1))  $(($x + 1))
+	field splitting
+		POSIX.1-2008 XCU 2.6.5
+		IFS is a set of delimiters, at which unquoted fields are split
+	pathname expansion
+		POSIX.1-2008 XCU 2.6.6
+		POSIX.1-2008 XCU 2.13
+		performed unless 'set -f' was run
+		patterns
+			? matches any single character
+			* matches multiple (0 or more) characters
+			[ opens RE bracket expansion
+		if pattern does not match any existing files
+			pattern string is left unchanged
+redirection
+	input redirection
+		[n]<word
+		n: optional file descriptor number (default: 0, stdin)
+		word: name of file
+	output redirection
+		[n]>word
+		[n]>|word
+		n default: 1, stdout
+	appending redirected output
+		[n]>>word
diff --git a/topics/topics.txt b/topics/topics.txt
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+++ b/topics/topics.txt
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+mdadm RAID
+Linux LVM2
+signals and threads
+introduction to the UNIX shell
+usage of dd
+overview of GNU Screen
+set up a server
+	do stuff with it, I don't know
+
+projects?
+	GNU/Linux or BusyBox/Linux, LFS-style
+	server