linux common commands
1.1 daily operations command
View current working directory
pwd
View the current system time
date
See who's online (who logged on to the server)
who view the current online
last View recent history of landing
1.2 file system operations
View Files
ls / View child nodes (folders and files) in the root directory information
ls -al -a show hidden files -l is in a more detailed form display
ll displayed in a list
ll -a show hidden files
Change directory
cd /home
Create a folder
mkdir aaa This is a relative path of the wording
mkdir -p aaa / bbb / ccc create a batch file path
mkdir / data which is written the absolute path
Delete the folder
You can delete empty directories rmdir
Delete all all child nodes rm -r aaa aaa can put the whole folder and the
rm -rf aaa aaa forced to delete
Edit folder name
mv aaa aa1
Create a file
touch fbb.txt create an empty file
echo "hello fbb"> fbb.txt and redirection ">" function, the output of an instruction to write to a file, overwrites the original contents of the file
echo "hello, liu yi fei" >> lyf.txt outputs an instruction result is appended to a file, do not overwrite the original file content
Operation 1.3 file permissions
Interpretation description format linux file permissions
drwxr-xr-x (may also be represented by a binary 111101101--> 755)
d: identifies the node type (d: Folder -: L File: Link)
r: read w: write x: Executable
The first group rwx: represents the owner of the file to its permissions: read-write executables
The second group rx: Specifies the file it belongs to the group of permissions: read, can not write, execute
Third group rx: Specifies the file to other users (with respect to the above two types of users) to its authority: read, and write, execute
Modify file permissions
chmod g-rw fbb.txt said it would fbb.txt rw privilege belongs to the group canceled
chmod o-rw fbb.txt said it would cancel its fbb.txt rw rights of others
chmod u + x fbb.txt said it would fbb.txt permission to increase their user x
It can also be used to digitally modify permissions
chmod 664 fbb.txt
Will be modified to rw-rw-r-: as = 664 110 110 100
If you want all the contents of a folder permissions unity modified, you can -R parameter
chmod -R 770 aaa/
chown the owner of the specified file to the specified user or group, the user may be a user name or a user ID; group may be a group name or group ID
chown Username: group name
chown fbb: fbb aaa / <only root can execute>
note:
When the directory does not have execute permissions ordinary users can not enter
Only the file read and write permissions, as long as the parent directory has execute permissions and modify, ordinary users can be deleted. (Delete files instead of modifying it, is the operating parent directory),
1.4 basic user management
Add user
useradd fbb
To modify the password to log in
passwd fbb prompted to enter a password to
Configuring sudo permissions for users
Edited by root vi / etc / sudoers
In the following location of the file, you can add a line to fbb
root ALL=(ALL) ALL
fbb ALL=(ALL) ALL
Then, fbb sudo user can use to perform system-level instructions
[fbb@min1~]$ sudo useradd hadoop
1.5 System Management Operation
View hostname
hostname
Modify the host name (after the restart invalid)
hostname min1fbb
Modify the host name (after the restart permanent)
vi /etc/sysconfig/network
Modify IP (after the restart invalid)
ifconfig eth0 192.168.33.161
Modify IP (after the restart permanent)
vi /etc/sysconfig/network-scripts/ifcfg-eth0
The external storage device mount to mount the file system
mkdir / mnt / cdrom to create a directory to mount
mount -t iso9660 -o ro / dev / cdrom / mnt / cdrom / device / dev / cdrom mounted to the mount point: / mnt / cdrom in
umount
umount /mnt/cdrom
Statistics size of a file or folder
du -sh /mnt/cdrom/Packages
df -h View disk space
Shutdown
halt
Restart
reboot
1.6 Configure the DNS server
Modify the mapping relationship ip address and host name
vi /etc/hosts
| 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 192.168.33.61 min1 192.168.33.62 min2 192.168.33.63 min3
|
Free secret ssh landing between 1.7 Host Configuration
If you want to log in min1 min2
On min1 operation:
First, generate a key pair
ssh-keygen (when prompted, you can directly enter)
Then min1 own public key and a copy of the authorization list appended to the file authorized_keys min2 in
ssh-copy-id min2
Verify the effect of:
ssh min2
| [root@min1 ~]# ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): Created directory '/root/.ssh'. Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /root/.ssh/id_rsa. Your public key has been saved in /root/.ssh/id_rsa.pub. The key fingerprint is: 96:b9:d1:66:55:78:cb:36:5e:dd:b2:0e:34:48:7e:00 root@min1 The key's randomart image is: + - [RS 2048] ---- + | E. .. | | the ... | | o oo .o | | + The + * +. | | S +o + = | | . =. the | | . the | | . | | | +-----------------+ [root@min1 ~]# |
| [root@min1 ~]# ssh-copy-id min2 root@ min2's password: 【hadoop】 Now try logging into the machine, with "ssh 'min2'", and check in:
.ssh/authorized_keys
to make sure we haven't added extra keys that you weren't expecting. |
|
[root@min1 ~]# ssh min2
Last login: Wed Jan 9 06:37:44 2019 from 192.168.33.2 [root@min2 ~]# [root@min2 ~]# |
1.8 minimal installation problems occurring in the system - missing command
Various commands will be missing, missing the various dependencies when installing software
scp命令没有，可以通过安装获得：yum install -y openssh-clients
集群中每台机器上都要安装才行