命令列一些技巧：
*

表示任意字元（也可以無字元）

?

任意一個單字元

[a-z]

包含一個字元範圍中的任一字元

[^a-z]

不包含此範圍的字元

Tab鍵

補齊命令名稱或其他名稱

history

重新輸入以前執行過的指令

	!+序號

^

替代上個命令中的某一段字元

	如^2^1 將上個命令中的1替換為2

~

進入家目錄(home directory)

	~root

	~user1

$

變數名

	如 echo $HOME

{}

排列組合

	a{a,b}=aa,ab

`` or $()

優先執行的命令

	echo "Hostname: `hostname`"

$[]

進行數學計算

	echo $[$a + $b]

\

後面的命令接著前面的

"

禁止所有特殊資源的功能，除了$ \ ` !

’

禁止所有特殊資源的功能

+. or +.

補齊上個命令的最後一個引數

set -o/+o vi

切換編輯模式

常用命令：
date
cal: calendar
pwd: parent working directory
cd: change directory
ls: list directory contents
cp: copy files and directories
mv: move and/or rename files and directories
rm: remove files
touch: create empty files or update file timestamps
mkdir: make a directory
rmdir: remove an empty directory
file: check file type
cat: view an entire text file
less: view text page by page
cut: display specific columns of file data
sort: sort text to standard out - original file unchanged
chmod: change access modes
df: report disk space usage(free)
du: report disk space usage(used)
tar: create/extract an archive
gzip: compress
bzip: compress
gunzip: extract
bunzip: extract
passwd: change password
su: start a new shell as a different user
sed: search and replace
head: display first few lines(default 10 lines) of text in a file
tail: display last few lines(default 10 lines) of text in a file
wc: “count lines, words and characters”
uniq: “remove successive, duplicate lines in a file”
paste: paste files together
tr: character translator
diff: version comparison
sdiff: version comparison
aspell: spell checking
expand: expand tabs into spaces
fmt: reformat text into paragraphs
pr: reformat text for printing
top: display snapshot of processes
vmstat: report virtual memory stats
free: summary of system memory usage
renice: change priority of a process
kill: send system signal to a process
fdisk: create partitions
partprobe: reinitialize the kernel in memory of the partition table
mke2fs: filesystem creation
lsattr: display file attributes
chattr: change file attributes
ln: linkname
alias: create shortcuts to commands
whoami: find out who you are
groups: find out what groups you belong to
id: find out what groups you belong to
users: find out who is logged in
who: find out who is logged in
w: find out who is logged in
last: login/reboot history