


1. View the currently logged in user information
who command:
The default output of who includes user name, terminal type, login date and remote host.
who /var/log/wtmp
You can view every login since the wtmp file was created
(1) -b: View the last system startup time
(2) -H: Print the title of each column
users command:
Print the currently logged in users, each displayed user name corresponds to a login session.
2. View command history
Each user has a command history record
View $HOME/.bash_history
Or enter in the terminal: history
3. last Command
ViewUser loginHistory
This command will read the /var/log/wtmp file; /var/log/btmp can display remote login information.
Last prints the login information of all users by default.
If you want to print the login information of a certain user, you can use
last Username
Options:
(1)-x: Display system power on and off and execution level information
(2)-a: Display login ip on the last line
(3) -f: Read a specific file, you can choose -f /var/log/btmp file
(4) -d: Convert the IP address to a host name
(5) -n: Set the display of the list Number of columns
(6) -t: View user login history at the specified time
For example:
last -t 20150226160404
Display the login history before this timestamp
4. Lastlog command
View the latest login history of all users
The command will read the /var/log/lastlog file; user The sorting order is according to the order in /etc/passwd
Options:
(1) -u: View the last login history of a user
For example: lastlog -u test
View the login history of user test
(2) -t: View the user login history in the past few days
For example: lastlog -t 1
View the login history within the last day
(3) -b: View the user login history before the specified number of days
For example: lastlog -b 60
View user login history 60 days ago
5, ac command
Report the user connection time (hours) based on the login and exit times in the /var/log/wtmp file, and the default output report is the total time
(1)-p: Display the connection time of each user
(2)-d: Display the daily connection time
(3) -y: Display the year, used in conjunction with -d
1. View the currently logged in user information
who command:
The default output of who includes user name, terminal type, login date and remote host.
who /var/log/wtmp
You can view every login since the wtmp file was created
(1) -b: View the last system startup time
(2) -H: Print the title of each column
users command:
Print the currently logged in users, each displayed user name corresponds to a login session.
2. View command history
Each user has a command history record
View $HOME/.bash_history
Or enter in the terminal: history
3. last Command
View user login history
This command will read the /var/log/wtmp file; /var/log/btmp can display remote login information.
Last prints the login information of all users by default.
If you want to print the login information of a certain user, you can use
last Username
Options:
(1)-x: Display system power on and off and execution level information
(2)-a: Display login ip on the last line
(3) -f: Read a specific file, you can choose -f /var/log/btmp file
(4) -d: Convert the IP address to a host name
(5) -n: Set the display of the list Number of columns
(6) -t: View user login history at the specified time
For example:
last -t 20150226160404
Display the login history before this timestamp
4. Lastlog command
View the latest login history of all users
The command will read the /var/log/lastlog file; the order of users is according to /etc/ Sequence
options in passwd:
(1) -u: View the last login history of a user
For example: lastlog -u test
View the login history of user test
(2) -t: View the user login history in the past few days
For example: lastlog -t 1
View the login history within the last day
(3) -b: View the user login history before the specified number of days
For example: lastlog -b 60
View user login history 60 days ago
5, ac command
Report the user connection time (hours) based on the login and exit times in the /var/log/wtmp file. The default output report is the total time
(1)-p: Display the connection time of each user
(2)-d: Display the daily connection time
(3)-y: Display the year, used with -d
The above is the detailed content of Linux User Management (3) Detailed explanation on how to view user login time and command history. For more information, please follow other related articles on the PHP Chinese website!

The five basic components of the Linux system are: 1. Kernel, 2. System library, 3. System utilities, 4. Graphical user interface, 5. Applications. The kernel manages hardware resources, the system library provides precompiled functions, system utilities are used for system management, the GUI provides visual interaction, and applications use these components to implement functions.

Linux maintenance mode can be entered through the GRUB menu. The specific steps are: 1) Select the kernel in the GRUB menu and press 'e' to edit, 2) Add 'single' or '1' at the end of the 'linux' line, 3) Press Ctrl X to start. Maintenance mode provides a secure environment for tasks such as system repair, password reset and system upgrade.

The steps to enter Linux recovery mode are: 1. Restart the system and press the specific key to enter the GRUB menu; 2. Select the option with (recoverymode); 3. Select the operation in the recovery mode menu, such as fsck or root. Recovery mode allows you to start the system in single-user mode, perform file system checks and repairs, edit configuration files, and other operations to help solve system problems.

The core components of Linux include the kernel, file system, shell and common tools. 1. The kernel manages hardware resources and provides basic services. 2. The file system organizes and stores data. 3. Shell is the interface for users to interact with the system. 4. Common tools help complete daily tasks.

The basic structure of Linux includes the kernel, file system, and shell. 1) Kernel management hardware resources and use uname-r to view the version. 2) The EXT4 file system supports large files and logs and is created using mkfs.ext4. 3) Shell provides command line interaction such as Bash, and lists files using ls-l.

The key steps in Linux system management and maintenance include: 1) Master the basic knowledge, such as file system structure and user management; 2) Carry out system monitoring and resource management, use top, htop and other tools; 3) Use system logs to troubleshoot, use journalctl and other tools; 4) Write automated scripts and task scheduling, use cron tools; 5) implement security management and protection, configure firewalls through iptables; 6) Carry out performance optimization and best practices, adjust kernel parameters and develop good habits.

Linux maintenance mode is entered by adding init=/bin/bash or single parameters at startup. 1. Enter maintenance mode: Edit the GRUB menu and add startup parameters. 2. Remount the file system to read and write mode: mount-oremount,rw/. 3. Repair the file system: Use the fsck command, such as fsck/dev/sda1. 4. Back up the data and operate with caution to avoid data loss.

This article discusses how to improve Hadoop data processing efficiency on Debian systems. Optimization strategies cover hardware upgrades, operating system parameter adjustments, Hadoop configuration modifications, and the use of efficient algorithms and tools. 1. Hardware resource strengthening ensures that all nodes have consistent hardware configurations, especially paying attention to CPU, memory and network equipment performance. Choosing high-performance hardware components is essential to improve overall processing speed. 2. Operating system tunes file descriptors and network connections: Modify the /etc/security/limits.conf file to increase the upper limit of file descriptors and network connections allowed to be opened at the same time by the system. JVM parameter adjustment: Adjust in hadoop-env.sh file


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft