[Linux Notebook 2] Manage File,Dir,User,Group

Root directory introduce:

dev : Device directory
etc : System software startup and config
home: User main directory
lib ：C complier directory/libary
mnt : host plug/unplug device
proc: System directory, process infomation
root: Super user main directory
tmp : temp file

sudo是superuser do的简写，sudo是linux系统管理指令，是允许系统管理员让普通用户执行一些或者全部的root命令的一个工具，如halt，reboot，su等等。这样不仅减少了root用户的登陆 和管理时间，同样也提高了安全性。

apt是个很完整和先进的软件包管理程式，使用他能够让您，又简单，又准确的找到您要的的软件包， 并且安装或卸载都很简洁。 他还能够让您的任何软件都更新到最新状态，而且也能够用来对ubuntu进行升级。

Basic Command:

mkdir
tangym@ubuntu:~$ mkdir test2 test3  --Create two diretories
tangym@ubuntu:~$ mkdir test1/mydir  --Create a folder under test1

tangym@ubuntu:~$ mkdir test100/mydir
mkdir: cannot create directory `test100/mydir': No such file or directory
tangym@ubuntu:~$ mkdir -p test100/mydir -- Force create the two folders, if test100 doesn't exist

touch
tangym@ubuntu:~$ touch hello -- Create the hello file in current directory

echo
tangym@ubuntu:~/test1$ cat hellobackup
tangym@ubuntu:~/test1$ echo "hello" > hellobackup -- Write "hello" to the file
tangym@ubuntu:~/test1$ cat hellobackup
hello

mv
tangym@ubuntu:~$ mv hello test1 -- move hello to test1 folder
tangym@ubuntu:~/test1$ mv hello hellobackup -- rename a file.

cp
tangym@ubuntu:~$ cp pse2 test2 -- copy file pse2 to test2 folder

rm/rmdir
tangym@ubuntu:~$ rm hello -- remove hello file
tangym@ubuntu:~$ rmdir test2 -- remove test2 folder

[Input] redirect:
tangym@ubuntu:~$ cat <<EOF >hellobackup
> hello world!
> real func
> EOF
tangym@ubuntu:~$ cat hellobackup
hello world!
real func
tangym@ubuntu:~$

|------Example(Create,remove file)--------|
tangym@ubuntu:~$ cd mhydir
tangym@ubuntu:~/mhydir$ ls
tangym@ubuntu:~/mhydir$ touch test
tangym@ubuntu:~/mhydir$ ls
test
tangym@ubuntu:~/mhydir$ rm test
tangym@ubuntu:~/mhydir$ ls
tangym@ubuntu:~/mhydir$ touch test
tangym@ubuntu:~/mhydir$ rm -i test   --Will Confirm whether delete the file
rm: remove regular empty file `test'? n
tangym@ubuntu:~/mhydir$ ls
test
tangym@ubuntu:~/mhydir$ rm -i test
rm: remove regular empty file `test'? y
tangym@ubuntu:~/mhydir$ ls
tangym@ubuntu:~/mhydir$
|--------End-----------|

File permission:
drwxr-xr-x  2           tangym            tangym           4096        May 29  2015 Desktop
          [LinkCount]  [CurrentUser]    [CurrentGroup]   [FileSize]  [CreationTime]
Field1: self permission
drwxr-
d:direcory
rwx: read,write,Execute,

Field2: current group's user permission
r-x:

Field3: other group's user permission
r-x

|------Change file owner and workgroup -----|
tangym@ubuntu:~$ mkdir mvhello
tangym@ubuntu:~$ ls -l mvhello
total 0
tangym@ubuntu:~$ ls -l
total 204136
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Desktop
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Documents
drwxr-xr-x  3 tangym tangym         4096 May 14 08:53 Downloads
-rw-r--r--  1 tangym tangym         8445 May 29  2015 examples.desktop
-rw-rw-r--  1 tangym tangym        10240 Jan 20  2011 ez_setup.py
drwxrwxr-x  2 tangym tangym         4096 May 24 23:37 mhydir
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Music
drwxrwxr-x  2 tangym tangym         4096 May 24 23:49 mvhello
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Pictures
-rw-rw-r--  1 tangym tangym            0 May 24 22:42 pse
-rw-rw-r--  1 tangym tangym            0 May 24 23:12 pse2
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Public
drwxrwxr-x  9 tangym tangym         4096 May 14 08:18 pycharm-community-2016.1.3
-rwxrw-rw-  1 tangym tangym    207707566 May 14 08:09 pycharm-community-2016.1.3.tar.gz
drwxrwxr-x  3 tangym tangym         4096 May 14 08:25 PycharmProjects
drwxrwxr-x  6 tangym tangym         4096 May 14 08:55 redis-2.8.12
-rw-rw-r--  1 tangym tangym      1215331 Jun 23  2014 redis-2.8.12.tar.gz
drwxrwxr-x 10 tangym tangym         4096 May 14 08:54 redis-py-master
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Templates
drwxrwxr-x  3 tangym tangym         4096 May 24 23:11 test1
drwxrwxr-x  3 tangym tangym         4096 May 24 22:38 test100
drwxrwxr-x  2 tangym tangym         4096 May 24 22:36 test3
drwxrwxr-x  2 tangym tangym         4096 May 17 21:52 TestFolder
drwxrwxr-x  2 tangym tangym         4096 May 29  2015 Ubuntu One
-rw-rw-r--  1 tangym tangym            0 May 17 21:49 Untitled Document
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Videos
drwxrwx---  2 lewis  workgroup      4096 May 24 22:25 work
tangym@ubuntu:~$ sudo chown lewis mvhello
[sudo] password for tangym:
tangym@ubuntu:~$ ls -l
total 204136
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Desktop
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Documents
drwxr-xr-x  3 tangym tangym         4096 May 14 08:53 Downloads
-rw-r--r--  1 tangym tangym         8445 May 29  2015 examples.desktop
-rw-rw-r--  1 tangym tangym        10240 Jan 20  2011 ez_setup.py
drwxrwxr-x  2 tangym tangym         4096 May 24 23:37 mhydir
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Music
drwxrwxr-x  2 lewis  tangym         4096 May 24 23:49 mvhello
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Pictures
-rw-rw-r--  1 tangym tangym            0 May 24 22:42 pse
-rw-rw-r--  1 tangym tangym            0 May 24 23:12 pse2
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Public
drwxrwxr-x  9 tangym tangym         4096 May 14 08:18 pycharm-community-2016.1.3
-rwxrw-rw-  1 tangym tangym    207707566 May 14 08:09 pycharm-community-2016.1.3.tar.gz
drwxrwxr-x  3 tangym tangym         4096 May 14 08:25 PycharmProjects
drwxrwxr-x  6 tangym tangym         4096 May 14 08:55 redis-2.8.12
-rw-rw-r--  1 tangym tangym      1215331 Jun 23  2014 redis-2.8.12.tar.gz
drwxrwxr-x 10 tangym tangym         4096 May 14 08:54 redis-py-master
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Templates
drwxrwxr-x  3 tangym tangym         4096 May 24 23:11 test1
drwxrwxr-x  3 tangym tangym         4096 May 24 22:38 test100
drwxrwxr-x  2 tangym tangym         4096 May 24 22:36 test3
drwxrwxr-x  2 tangym tangym         4096 May 17 21:52 TestFolder
drwxrwxr-x  2 tangym tangym         4096 May 29  2015 Ubuntu One
-rw-rw-r--  1 tangym tangym            0 May 17 21:49 Untitled Document
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Videos
drwxrwx---  2 lewis  workgroup      4096 May 24 22:25 work
tangym@ubuntu:~$ whatis chgrp
chgrp (1)            - change group ownership
tangym@ubuntu:~$ sudo chgrp workgroup mvhello
tangym@ubuntu:~$ ls -l
total 204136
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Desktop
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Documents
drwxr-xr-x  3 tangym tangym         4096 May 14 08:53 Downloads
-rw-r--r--  1 tangym tangym         8445 May 29  2015 examples.desktop
-rw-rw-r--  1 tangym tangym        10240 Jan 20  2011 ez_setup.py
drwxrwxr-x  2 tangym tangym         4096 May 24 23:37 mhydir
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Music
drwxrwxr-x  2 lewis  workgroup      4096 May 24 23:49 mvhello
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Pictures
-rw-rw-r--  1 tangym tangym            0 May 24 22:42 pse
-rw-rw-r--  1 tangym tangym            0 May 24 23:12 pse2
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Public
drwxrwxr-x  9 tangym tangym         4096 May 14 08:18 pycharm-community-2016.1.3
-rwxrw-rw-  1 tangym tangym    207707566 May 14 08:09 pycharm-community-2016.1.3.tar.gz
drwxrwxr-x  3 tangym tangym         4096 May 14 08:25 PycharmProjects
drwxrwxr-x  6 tangym tangym         4096 May 14 08:55 redis-2.8.12
-rw-rw-r--  1 tangym tangym      1215331 Jun 23  2014 redis-2.8.12.tar.gz
drwxrwxr-x 10 tangym tangym         4096 May 14 08:54 redis-py-master
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Templates
drwxrwxr-x  3 tangym tangym         4096 May 24 23:11 test1
drwxrwxr-x  3 tangym tangym         4096 May 24 22:38 test100
drwxrwxr-x  2 tangym tangym         4096 May 24 22:36 test3
drwxrwxr-x  2 tangym tangym         4096 May 17 21:52 TestFolder
drwxrwxr-x  2 tangym tangym         4096 May 29  2015 Ubuntu One
-rw-rw-r--  1 tangym tangym            0 May 17 21:49 Untitled Document
drwxr-xr-x  2 tangym tangym         4096 May 29  2015 Videos
drwxrwx---  2 lewis  workgroup      4096 May 24 22:25 work

[Example-------Create Users and share group-----]
---Create workgroup----
tangym@ubuntu:~$ sudo groupadd workgroup
[sudo] password for tangym:

---Create four users and password----
tangym@ubuntu:~$ sudo useradd -G workgroup lucy
tangym@ubuntu:~$ sudo passwd lucy
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

tangym@ubuntu:~$ sudo useradd -G workgroup lewis
tangym@ubuntu:~$ sudo passwd lewis
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

tangym@ubuntu:~$ sudo useradd -G workgroup mike
tangym@ubuntu:~$ sudo passwd mike
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

tangym@ubuntu:~$ sudo useradd -G workgroup peter
tangym@ubuntu:~$ sudo passwd peter
Enter new UNIX password:
Retype new UNIX password:

-----Create direcories
tangym@ubuntu:~$ cd /home
tangym@ubuntu:/home$ sudo mkdir work -- Create direcory
tangym@ubuntu:/home$ sudo chgrp workgroup work -- update a directory belonged group.
tangym@ubuntu:/home$ sudo chmod g+rwx work -- g+  rws: read,write,execute
tangym@ubuntu:/home$ sudo chmod o-rwx work -- o: other, remove other group's permission.
tangym@ubuntu:/home$ sudo chown lewis work -- set the group lead to lewis.