• GPIO举例
  

• 内核：ARM920T
• 16/32位RICS体系结构

• Ctrl+Alt+T启动

• 查看环境变量路径

  • echo $PATH

• 设置PATH环境变量添加我们自己的目录：

  • exprot PATH=$PATH:/my/dir

• 文件设置可执行权限：

  • chomd +x 文件名

• ~表示家目录
• $表示普通用户
• #表示root管理员

• 命令 [选项] [参数]

eg:

• ls
• ls -l
• ls -l /home

• pwd
  • 打印当前所在路径（print working directory）

• cd
  • 切换路径（change directory）
    • cd ~ 切换至当前用户的家目录
    • cd . 切换至当前路径
    • cd … 切换至上一级路径
    • cd …/… 切换至上上级路径
    • cd - 切换至上一次路径

• ls
  • 列出目录内容（list）
    • -l（long的缩写）显示目录下详细的信息（文件权限、最后修改时间、文件大小）
    • -a（all的缩写）显示了隐藏文件（以.为开头为隐藏文件）
    • -h（human-able的缩写）将文件大小以K（KB）、M（MB）、G（GB）来表示

• mkdir
  • 创建目录（make directory）
    • mkdir dir0 创建dir0这个目录
    • mkdir -p 父目录/子目录

• rmdir
  • 删除目录（remove directory）
    • 不能删除非空目录
    • rm -r 即可删除非空目录（-r为递归删除的含义：意思是删除当前目录下所有文件和文件夹）

• mv
  • 重命名/移动（move）
  • mv 旧文件名 新文件名（修改文件名）
  • mv 旧目录名 新目录名（修改目录名）
  • mv 文件名 目录名（移动路径）

• touch
  • 新建文件

• cp
  • 复制（copy）
    • cp -r dir1 dir2 复制dir1目录下所有内容至dir2（-r参数为递归复制）

• rm
  • 删除文件（remove）
    • rm -i file 删除文件file前，要求你是否同意删除（y表示同意，n表示取消）
    • rm -r dir 删除整个dir目录
    • rm -ir dir 删除目录dir前，要求你是否同意删除其中的每一个文件（每次都会询问）

• cat
  • 查看（catenate）
    • cat -n file 以显示行号的方式输出

• clear
  • 刷新屏幕（保留历史命令记录）

• reset

  • 重新初始化屏幕（清除历史命令记录）

• man

  • 手册、帮助（manual）
  • man man 查看man命令含义
  • man 2 open 查看open库函数含义
    • 1 可执行程序或 shell 命令
      2 系统调用(内核提供的函数)
      3 库调用(程序库中的函数)
      4 特殊文件(通常位于 /dev)
      5 文件格式和规范，如 /etc/passwd
      6 游戏
      7 杂项(包括宏包和规范，如 man(7)，groff(7))
      8 系统管理命令(通常只针对 root 用户)
      9 内核例程

• wc
  • 统计（word count）
  • 统计（行数、字数、大小）

• ps
  • 进程状态查看（processes status ）
  • ps -aux

• kill
  • 关闭进程（kill后接 进程PID号）

• uname
  • 查看系统名称（unix name）

• rm -rf /*
  Linux的目录是使用 / 之类的目录形式存放，rm 是Linux的删除命令，后面带的“-rf”，"-r"指的是 递归删除（意思是删除当前目录下所有文件和文件夹），而“-f”指的是 强制删除 。后方的/*指的是 根目录“/”下的所有文件。即删除根目录下所有内容。

• /home/pi 是绝对路径
• 相对路径一般以.或…构成
  • 当前路径为/bin，./pwd就是直接执行pwd程序
  • 当前路径为/home/pi/Picture，输入cd …/Music 切换至/home/pi/Music

linux 命令英文全称

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 = ETCetera 
/lib = LIBrary 
/proc = PROCesses 
/sbin = Superuser BINaries 
/tmp = TeMPorary 
/usr = Unix Shared Resources 
/var = VARiable ? 
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