ls:list
cd:Change Directory
su:switch user
pwd:print work directory
ps:process status
rmdir:Remove Directory
rm:Remove
cat:concatenate
ln:Link files
ln -s:link -soft
mkdir:Make Directory
man:Manual
cd:Change directory
ps:Process Status
mkfs:Make file system
fsck:File system check
uname:Unix name
lsmod:List modules
mv:Move file
cp:Copy file
fg:Foreground
bg:Background
chown:Change owner
chgrp:Change group
chmod:Change mode
chsh:CHange SHell
umount:Unmount
dd:Convert an copy
tar:Tape archive
ldd:List dynamic dependencies
insmod:Install module
rmmod:Remove module
lsmod:List module
*.rc:Resource configuration
*.a:Archive,static library
*.so:Shared object,dynamically linked library
*.o:Object file,complied result of C/C++ source file
rpm:Red hat package manager
dpkg:Debian package manager
apt:Advanced package tool
bin:BINaries
/dev:DEVices
/etc:ETCetera
/lib:LIBrary
/proc:PROCesses
/sbin:Superuser BINaries
/tmp:TeMPorary
/usr:Unix Shared Resources 
/var:VARiable
/boot:boot
FIFO:First In, First Out
GRUB:GRand Unified Bootloader
IFS:Internal Field Seperators
LILO:LInux LOader
PS:Prompt String
Perl:Pratical Extraction and Report Language=Pathologically Eclectic Rubbish Lister
Tcl:Tool Command Language
Tk:ToolKit
VT:Video Terminal
YaST:Yet Another Setup Tool
apache:a patchy server
ar:archiver
as:assembler
awk:Aho Weiberger and Kernighan
bash:Bourne Again SHell
bc:Basic(Better)Calculator
bg:BackGround
cal:CALendar
cat:CATenate
cmp:compare
cobra:Common Object Request Broker Architecture
comm:common
cpio:CoPy In and Out
cpp:C Pre Processor
cron:Chronos
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
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 = 拟声 又 = 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, rc还是plan9的shell
rev = REVerse
rm = ReMove
rn = Read News
roff = RunOFF
rpm = RPM Package Manager = RedHat Package Manager
rsh, rlogin, rvim中的r = Remote
rxvt = ouR XVT
seamoneky = 我
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
tee = T (T形水管接口)
telnet = TEminaL over Network
termcap = terminal capability
terminfo = terminal information
tex = τέχνη的缩写，希腊文art
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
Fish = the Friendly Interactive SHell
su = Switch User
MIME = Multipurpose Internet Mail Extensions
ECMA = European Computer Manufacturers Association