su: Swith user 切换用户，切换到root用户
cat: Concatenate 串联
uname: Unix name 系统名称
df: Disk free 空余硬盘
du: Disk usage 硬盘使用率
chown: Change owner 改变所有者
chgrp: Change group 改变用户组
ps: Process Status 进程状态
tar: Tape archive 解压文件
chmod: Change mode 改变模式
umount: Unmount 卸载
ldd: List dynamic dependencies 列出动态相依
insmod: Install module 安装模块
rmmod: Remove module 删除模块
lsmod: List module 列表模块
alias: Create your own name for a command
bash: GNU Bourne-Again Shell linux内核
grep: global regular expression print
httpd: Start Apache
ipcalc: Calculate IP information for a host
ping: Send ICMP ECHO_Request to network hosts
reboot: Restart your computer
sudo: Superuser do

/bin: BINaries
/dev: DEVices
/etc: 存放配置文件的地方。配置文件的目录
   Editable Text Configuration 初期etcetra directory（ETCetera）, 后来"Editable Text Configuration" 或者 "Extended Tool Chest"
/opt: Optional application software packages
pwd: print working Directory (打印工作目录)
/lib: LIBrary
/proc: PROCesses
/sbin: Superuser BINaries
/tmp: TeMPorary
/usr: Unix Shared Resources
/var: VARiable ? 是储存各种变化的文件，比如log等等
FIFO: First In, First Out
GRUB: GRand Unified Bootloader
IFS: Internal Field Seperators
LILO: LInux LOader
MySQL: My最初作者的名字, SQL:Structured Query Language
PHP: Personal Home Page Tools, PHP Hypertext Preprocessor
PS: Prompt String
Perl: "Pratical Extraction and Report Language": "Pathologically Eclectic Rubbish Lister"
Python: Monty Python's Flying Circus
Tcl: Tool Command Language
Tk: ToolKit
VT: Video Terminal
YaST: Yet Another Setup Tool
apache: "a patchy" server
apt: Advanced Packaging Tool
ar: archiver
as: assembler
bash: Bourne Again SHell
bc: Basic (Better) Calculator
bg: BackGround
cal: CALendar
cat: CATenate
cd: Change Directory
chgrp: CHange GRouP
chmod: CHange MODe
chown: CHange OWNer
chsh: CHange SHell
cmp: compare
cobra: Common Object Request Broker Architecture
comm: common
cp: CoPy
cpio: CoPy In and Out
cpp: C Pre Processor
cups: Common Unix Printing System
cvs: Current Version System
daemon: Disk And Execution MONitor
dc: Desk Calculator
dd: Disk Dump
df: Disk Free
diff: DIFFerence
dmesg: diagnostic message
du: Disk Usage
ed: editor
egrep: Extended GREP
elf: Extensible Linking Format
elm: ELectronic Mail
emacs: Editor MACroS
eval: EVALuate
ex: EXtended
exec: EXECute
fd: file descriptors
fg: ForeGround
fgrep: Fixed GREP
fmt: format
fsck: File System ChecK
fstab: FileSystem TABle
fvwm: F*** Virtual Window Manager
gawk: GNU AWK
gpg: GNU Privacy Guard
groff: GNU troff
hal: Hardware Abstraction Layer
joe: Joe's Own Editor
ksh: Korn SHell
lame: Lame Ain't an MP3 Encoder
lex: LEXical analyser
lisp: LISt Processing: Lots of Irritating Superfluous Parentheses
ln: LiNk
lpr: Line PRint
ls: list
lsof: LiSt Open Files
m4: Macro processor Version 4
man: MANual pages
mawk: Mike Brennan's AWK
mc: Midnight Commander
mkfs: MaKe FileSystem
mknod: MaKe NODe
motd: Message of The Day
mozilla: MOsaic GodZILLa
mtab: Mount TABle
mv: MoVe
nano: Nano's ANOther editor
nawk: New AWK
nl: Number of Lines
nm: names
nohup: No HangUP
nroff: New ROFF
od: Octal Dump
passwd: PASSWorD
pg: pager
pico: PIne's message COmposition editor
pine: "Program for Internet News & Email": "Pine is not Elm"
ping: Packet InterNet Grouper
pirntcap: PRINTer CAPability
popd: POP Directory
pr: pre
printf: PRINT Formatted
ps: Processes Status
pty: pseudo tty
pushd: PUSH Directory
pwd: Print Working Directory
rc: runcom: run command, shell
rev: REVerse
rm: ReMove
rn: Read News
roff: RunOFF
rpm: RPM Package Manager: RedHat Package Manager
rsh, rlogin,: Remote
rxvt: ouR XVT
sed: Stream EDitor
seq: SEQuence
shar: SHell ARchive
slrn: S-Lang rn
ssh: Secure SHell
ssl: Secure Sockets Layer
stty: Set TTY
su: Substitute User
svn: SubVersioN
tar: Tape ARchive
tcsh: TENEX C shell
telnet: TEminaL over Network
termcap: terminal capability
terminfo: terminal information
tr: traslate
troff: Typesetter new ROFF
tsort: Topological SORT
tty: TeleTypewriter
twm: Tom's Window Manager
tz: TimeZone
udev: Userspace DEV
ulimit: User's LIMIT
umask: User's MASK
uniq: UNIQue
vi: VIsual: Very Inconvenient
vim: Vi IMproved
wall: write all
wc: Word Count
wine: WINE Is Not an Emulator
xargs: eXtended ARGuments
xdm: X Display Manager
xlfd: X Logical Font Description
xmms: X Multimedia System
xrdb: X Resources DataBase
xwd: X Window Dump
yacc: yet another compiler compiler