user related commands
| useradd username | Add user |
| useradd -g groupname username | Add user to group |
| passwd username | set password |
| id username | View the details of the username |
| cat /etc/passwd | Check which users have been created |
| su username | Switch username (can't get environment variables) |
| su - username | Obtain environment variables and execute permissions) |
| userdel username | delete username |
| userdel -r username | The directory of the user name Yu user is also deleted |
| who am i | View login information |
| sudo username | Set ordinary users to have root permissions [vim etc/sudoers modification] |
| usermod -g usergroup username | Modify a user's initial login group |
Commands related to user groups
| groupadd group name | Add new group |
| groupdel group name | delete group |
| groupmod -n new group name old group name | modify group name |
| cat /etc/group | See what groups are created |
file permission class
chmod change permissions
Method 1: chmod { {ugoa}+-={rwx}} file or directory
Method 2: chmod number (777 binary: 111 111 111) file directory
chown change owner
chown -R end user user file or directory
chgrp change group
chgrp end user group file or directory
search for class
| find 【Search range】【Options】{-name<query method> -user<username> -size<file size>} |
| Use updatedb as much as possible before locate search files |
| grep filter search and "|" pipe character |
| eg：ls | grep - n initial-setup-ks.cfg |
compression and decompression
gzip files (can only compress files)
gunzip filename.gz
zip [-r] compressed directory
unzip [-d] <directory> specifies the directory where the decompressed files are stored
tar package
options
| -c | Generate a .tar package file |
| -v | show details |
| -f | Specify the file name after pressing the lock |
| -z | Unzip while packing |
| -x | Extract the .tar file |
| -C | Unzip to the specified directory |
-zcvf file name [use together but f must be put at the end] package
-zxvf filename unzip to current folder
Disk View and Partition Class
du View the disk usage of files and directories
du [option] file|directory
options
| -h | show friendly information |
| -a | View not only subdirectory size, but also files |
| -c | After displaying all file and subdirectory sizes, also display the total |
| -s | only show sum |
| -max-depth=n | Specify the depth of the statistics subdirectory as the level |
df view disk usage
df -h lists the overall disk usage of the file system to view the file system occupancy
lsblk View the mounting status of the device
lsblk -f View device mount status
mount|umount mount|unmount
mount 【-t vfstype】【-o option】 device dir
umount device file name or mount point
Set up automount
vi /etc/fatab
fdisk partition
fdisk -l View disk partition details
fdisk hard disk device name (partition operation)
m display command list p display current disk partition n add new partition w write partition information and exit q exit without saving partition information
Use mkfs -t xfs to specify the file system type for formatting
Process management class
ps View the process status of the current system
options
| a | Show all processes of all users with a terminal |
| x | List all processes of the current user, including processes without a terminal |
| u | friendly display |
| -e | list all processes |
| -u | List processes associated with a user |
| -f | Show a list of all processes in full format |
ps aux cpu share
ps -ef parent process ID of the process
kill terminates the process
pstree [-p display process ID||-u display process user]
top 实时监控系统进程状态
netstat 显示网络状态和端口占用信息
netstat -anp|grep 进程号
netstat -nlp|grep 端口号
crontab 系统定时任务
【1】启动服务 systemctl restart crond
【2】基本语法 crontab 【选项】
| -e | 编辑crontab的定时任务 |
| -l | 查询crontab任务 |
| -r | 删除当前用户的crontab的任务 |
举例每隔1分钟向hello 文件中写入一个a字符
*1 * * * * echo "a" >> /root/hello