Information about how-to use different aspects of the command line (also referred to as Shell, Terminal, Console and CLI)

General
CommandLine software list
BASH quick tips
How to copy and paste from terminal

CommandLine Shells (CLI)
About Shells
Ash
Bash
BusyBox - Linux utilities all-in one
Sh

Commands
AshCommands
BashCommands
BootParameters

e2fsprogs
e2fsck ext2/3/4 filesystem check

File Checks
md5sum - hash check
sha1sum - hash check

Linux Environment Variables
env - this command lists all the variables present
PATH

e2fsprogs ext2/3/4 filesystem management

Online Commandlines
http://www.goosh.org/
http://cb.vu/
http://www.masswerk.at/jsuix/

General
Basic Shell (Console) operation for beginners
The Text-User Interface
Learning the shell
Bash Introduction
Most popular commands by vote