Linux

What is Linux? Linux is a clone of the operating system UnIX, written from scratch by LinusTorvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX and Single UnIX Specification compliance.

It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management, and Tcp/IP networking.

Linux was first developed for 32-bit x86-based PCs (386 or higher). These days it also runs on (at least) the Compaq AlphaAXP, SunSPARC and UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64 and CRIS architectures.

Linux is easily portable to most general-purpose 32- or 64-bit architectures as long as they have a paged memory management unit (PMMU) and a port of the GNU C compiler (gcc).

Some basic linux commands, just practice them with all the information you got below:

								HINTS
man	show manual page on command				man commandnamename
ls	list files in directory					ls -a -l -R
cd	change working directory				cd
pwd	print working directory					pwd
du	show disk use of file(s) or directory			du -s
df	show free disk space					df
cp	copy a file or directory				cp -d -p -R
rm	remove a file or directory				rm -r -f
mv	move file or directory to another place			move file1 file2
mkdir	make directory						mkdir newdir
rmdir	remove directory					rmdir newdir
touch	change file timestamps					touch -t 10210000 filename
chmod	change file access permissions				chown guest.users filename
chown   change owner and group of a file			chmod u+x filename, chmod 770 filename
find	find files on name, date, owner, permissions etc	find ./ -name *.kdelnk

echo  	display a line of text					echo "Hello world"
cat     concatenate files and print on standard output		cat >test , cat file1 file2 >file3
more	view text file screen by screen				more textfile
less	a better version of more				less textfile
pico    edit a text file					pico filename
vi	the unix text editor					vi filename
head	show first lines of text file				head textfile
tail	show last lines of text file				tail -f textfile
wc	count bytes, words and lines in files			wc filename
grep	print lines matching a pattern				ls -alR |grep txt
tr	translete or delete characters				echo "test" | tr [:lower:] [:upper:]
sort	sort a file						sort filename
uniq	show only the diffenent lines from a text file		uniq filename
cmp	compare to files					cmp file1 file2
diff	find differences between two files			diff -u file1 file2

ps	show currently running processes			ps aux
jobs	show running or stopped jobs				jobs
fg	bring a process to the foreground			fg [jobnr]
kill	kill a process						kill -9 PID
killall	kill process by name					killall -9 netscape, killall -HUP daemon

uptime	show the time the system is running (and system load)	uptime
yes	output a string repeatedly until killed			yes hallo
top	display top CPU processes				top
date	show system date					date
who	show who is logged on					who
whoami	print effective userid					whoami
bc	binary calculator					bc

Some network stuff:

lynx	A text browser						lynx http://squat.net/ascii
telnet	Remote login						telnet dds.dds.nl
ping	Send small package to check if a machine is up & reaction time	ping localhost
ssh	A more secure version of telnet				ssh -l username host.domain
netstat Show network statistics					netstat -r
ftp     File transfer protocol					ftp ftp.nluug.nl
ncftp   A better ftp						nftp -u username ftp.nluug.nl
mail	Basic mail implementation				echo "Test" | mail -s "Test" guest
pine	A mail client						pine
irc	Internet Relay Chat					irc -c #squat guest03_ irc.xs4all.nl

These commands are very hard to use if you never used them before. The best way to find information on how to use them is the man command. This command tells you a lot of specific information on a command. Try man man for a start...

Some handy function keys:

[CTRL]-z		Bring a program to the background
[CTRL]-c		Stop a program
[CTRL]-d		End of input file
[ALT]-[F1]..[F6]	Switch to terminal TTY1..6 (depends on configuration)
[ALT]-[F7]		Switch to X (if running)
[CTRL]-[ALT]-[F1..6]	Switch from X to text terminal
[CTRL]-[ALT]-[BACKSP]	Kill X-window (in mode 5, X will restart)
[CTRL]-[ALT]-[DEL]	Reboot or halt (depends on configuration)

copied from: http://www.puscii.nl/