How to change SELinux mode

The steps to install Docker include updating the system and installing dependencies, adding GPG keys and repositories, installing the Docker engine, configuring user permissions, and testing the run. 1. First execute sudoaptupdate and sudoaptupgrade to update the system; 2. Install apt-transport-https, ca-certificates and other dependency packages; 3. Add the official GPG key and configure the warehouse source; 4. Run sudoaptinstall to install docker-ce, docker-ce-cli and containerd.io; 5. Add the user to the docker group to avoid using sudo; 6. Finally, dock

To restart the service managed by systemctl in Linux, 1. First use the systemctlstatus service name to check the status and confirm whether it is necessary to restart; 2. Use the sudosystemctlrestart service name command to restart the service, and ensure that there is administrator privileges; 3. If the restart fails, you can check whether the service name is correct, whether the configuration file is wrong, or whether the service is installed successfully; 4. Further troubleshooting can be solved by viewing the log journalctl-u service name, stopping and starting the service first, or trying to reload the configuration.

Bash scripts handle command line parameters through special variables. Use $1, $2, etc. to get positional parameters, where $0 represents the script name; iterates through "$@" or "$*", the former retains space separation, and the latter is merged into a single string; use getopts to parse options with parameters (such as -a, -b:value), where the option is added to indicate the parameter value; at the same time, pay attention to referring to variables, using shift to move the parameter list, and obtaining the total number of parameters through $#.

The shutdown command of Linux/macOS can be shut down, restarted, and timed operations through parameters. 1. Turn off the machine immediately and use sudoshutdownnow or -h/-P parameters; 2. Use the time or specific time point for the shutdown, cancel the use of -c; 3. Use the -r parameters to restart, support timed restart; 4. Pay attention to the need for sudo permissions, be cautious in remote operation, and avoid data loss.

ping is the basic tool for judging network connection status. The usage method is as follows: 1. Open the command line tool (cmd for Windows, Terminal for macOS/Linux); 2. Enter the ping command to add the target address, such as pingwww.example.com or ping8.8.8.8; 3. You can add parameters to limit the number of times, such as -n for Windows, and -c for macOS/Linux. The normal response displays time, packet loss may indicate a network problem, the timeout may be caused by firewall intercept or the host is not online, the unreachable prompts an abnormality in the local network, and if the domain name resolution fails, DNS needs to be checked. Although practical, some servers block pings, which can be accessed by browsers or tr

To view the status of services in Linux system, 1. Use systemctl to view all service status, pay attention to the UNIT and ACTIVE columns to determine whether the service is running; 2. Use systemctlstatus to view the detailed status of specific services, including operation status, PID and log summary; 3. View the service logs through journalctl-u, and locate issues in combination with the -f, --since or -n parameters; handling of common problems includes starting the service, checking the configuration, checking the cause of the crash and setting up the startup. Mastering these commands can effectively manage and troubleshoot service problems.

vmstat is a tool in Linux for monitoring system performance, which can view memory, CPU, IO, and process status. Run vmstat to output system snapshots, and add parameters such as vmstat2 to refresh every 2 seconds; common parameters include -s (summary), -d (disk statistics), and -p (partition information). The output is divided into fields such as procs(r, b), memory(swpd, free, buff, cache), swap(si, so), io(bi, bo), system(in, cs), cpu(us, sy, id, wa) and so on. In actual combat, if the r value is greater than the number of CPU cores, it may be overloaded. High Wa indicates the IO bottleneck, and continuous so does not mean that the memory is tight.

To create a file system, you need to use the mkfs command, and its basic format is sudomkfs. File system type partition path, such as sudomkfs.ext4/dev/sdb1; common supported file systems include ext4, vfat, ntfs, xfs, etc.; you can use -L to set volume labels, -c to check bad blocks and other options to enhance operation flexibility; at the same time, you can also use graphics tools such as GParted or Disks to simplify the process, but you must confirm the partition path before operation to avoid accidentally deletion of data.