Linux basic learning review notes

** Kernel and distribution

LInux itself is the kernel (kernel) of an operating system. Only the kernel cannot run, and a batch of corresponding applications need to be combined to form a collection, which is what we want. This aggregate is the distribution **

Such as Red Hat Redhat, ubuntu is a different distribution

Basic command:

1、ls

ls -l display list details
ls -a can display all files, including hidden files
ls -l -a

2、cd

Switch directory
cd . (to the current directory) eg: ./xx.sh Execute the sh file There is a xx.sh file in the current directory
cd .../ (upper layer)
cd
. Current directory
... Upper directory
— previous directory
/ root directory
~ Home directory of the former user (shortcut key
cd ~ for the home directory) (similar to the default storage space for documents, pictures and other files in Windows) Each user has a home directory, ordinary users are /home/username, root users Yes /root multi-user system
$ common user command line prompt
# root user command line prompt
observe the content of ls -la in the new directory

3. Absolute path (starting from the root directory), relative path (starting from the current directory) / 4. The current absolute path of
pwd /
5. mv to move the file (you can also rename it)
6. cp copy the file

cp -r copy folder
cp -f force
cp -rf

7. touch file
8. mkdir folder

mkdir -p abc/abc concatenation creates empty folders

9. rm file/folder deletion

rm -r delete folder
rm -f (force force delete)

10. rmdir can only delete empty folders

11. The cat file directly displays the file content on the command line

12. ln -s source file target connection file

Soft link, consistent connection, similar to Windows shortcut master-slave relationship
Hard link ln The equal relationship is different from copy, the essence is that there is only one file, similar to the death-free gold medal

13. man offline help manual

man 1 ls xxx linux command
man 2 ls xxx linux api
man 3 ls xxx c library function

14. apt-get install vim installation software

apt-get remove vim uninstall purge

ls -l
first character - dlp (pipeline file pipe) s (socket file)

15、they are root

Normal user switch to root user, need password
Switch between common users, need password
root Switch normal user without password

Sudo temporarily obtains root privileges and executes only one command without switching directories

16. Permission
d rwx rx rw-

前三个是属主对文件的操作权限
中间三个代表属主所在组的操作权限
后面三个代表其他组内的对文件的操作权限

r  可读   w   可写   x   可执行  -不可以
4				2					1
x不是想当然设置的，要看文件本身能不能运行！！！

17. Modify permissions:

(1) Directly change permissions chmod 744 file name
(2) Original basic addition and deletion permissions
owner u owner group g other o
chmod u+x file name
chmod gx file name
chown owner file name modify owner chgrp modify owner the group you are in

Advanced commands are not commonly used

1、find

Find files (hard disk search) find path -name When to use "'filename'" ? Generally know the file name, but do not know which path

2、grep

Find the content in the file, check a certain word grep -nr [option]
"word to search" file name

3、which 和whereis

Function to find a binary file (applications such as ls, vim, mkdir) The difference is which only displays the path of the binary file whereis
displays the path of the binary file, source code, man manual, etc., more detailed

4、unname

查看系统信息
uname -a

5. Shutdown -h now shut down immediately

shutdown  -r  now 立即重启
init  0      关机    init  2    重启
reboot  重启

6. tree (requires installation) to display the relationship structure of directory files

7. mount and unmount

挂载磁盘到文件系统

eg : mount  -t nfs -o nolock   ip:/root/path  /mnt
eg: unmount /mnt

8. Disk space management

df -h  显示已挂载分区列表
du -h  显示文件或文件夹的大小

9. User management

useradd  张三  创建用户
userdel 张三   删除用户
passwd  张三  密码   设置张三用户密码

10. File packaging, compression and decompression

tar -czvf   dir.tar.gz   dir/
tar -cjvf   dir.tar.bz2   dir/
tar -zxvf   dir.tar.gz
tar -jxvf   dir.tar.bz2
c  解压    x 打包
z  gz方式    j  bz2方式

d'affaires ******

• Build a server to format the file system sed and awk

• Network configuration Virtual machine Internet bridge mode NAT host only (only host mode)

  NAT： 修改/etc/network/interfaces    auto eth0下的inter  static为dhcp
  执行/etc/init.d/networking restart   重启网卡