内容一：Linux 版本整体信息的查看
# cat /etc/*release*内容二：Linux 版本某项具体信息的查看
2.1 查看此系统属于哪种 Linux
# lsb_release -i -s 2> /dev/null2.2 查看此系统的本版
# lsb_release -r -s 2> /dev/null2.3 查看此系统的内核版本
# uname -r 2> /dev/nullNo-cost subscription for open source world
Red Hat no cost subscription : Red Hat Developer Subscription for Individuals
The main function of this license is that can let we access Red Hat knowledge-based articles for individual development purpose
https://developers.redhat.com/products/rhel/download
[内容] Linux 系统重启时间的查看
正文：
方法一：使用 who -b 命令查看系统重启时间
$ who -b
system boot 2024-09-16 17:52方法二：使用 last 命令查看系统重启时间
2.1 使用 last 命令查看系统重启时间
$ last | grep "reboot" | head -1
reboot system boot 6.8.0-44-generic Mon Sep 16 17:52 still running或者：
$ last reboot | head -1
reboot system boot 6.8.0-44-generic Mon Sep 16 17:52 still running或者：
$ last reboot -n 1
reboot system boot 6.8.0-44-generic Mon Sep 16 17:52 still running
wtmp begins Wed Aug 14 10:01:22 20242.2 使用 last 命令查看系统重启时间并精确到秒
$ last reboot -F
reboot system boot 6.8.0-44-generic Mon Sep 16 17:52:25 2024 still running
reboot system boot 6.8.0-41-generic Fri Sep 6 21:53:12 2024 - Mon Sep 16 17:52:18 2024 (9+19:59)
wtmp begins Wed Aug 14 10:01:22 2024方法三：使用 uptime 命令查看系统重启时间并精确到秒
3.1 使用 uptime 命令查看系统重启时间并精确到秒
$ uptime -s
2024-09-16 17:52:233.2 使用 uptime 命令查看系统重启时间并精确到秒 （以显示 top 命令的第一行的形式）
$ uptime
15:16:17 up 14 days, 21:23, 3 users, load average: 0.15, 0.13, 0.063.3 使用 uptime 命令查看系统重启后已运行的时间
$ uptime -p
up 2 weeks, 21 hours, 24 minutes方法四：使用 top 命令查看系统重启时间并精确到秒
4.1 使用 top 命令查看系统重启时间并精确到秒
$ top -bn 1 | head -1
top - 15:40:47 up 14 days, 21:48, 3 users, load average: 0.02, 0.03, 0.014.2 使用 top 命令查看系统重启时间 （实时显示）
$ top
top - 15:42:19 up 14 days, 21:49, 3 users, load average: 0.00, 0.02, 0.00
Tasks: 289 total, 1 running, 287 sleeping, 0 stopped, 1 zombie
%Cpu(s): 2.2 us, 2.2 sy, 0.0 ni, 93.3 id, 0.0 wa, 0.0 hi, 2.2 si, 0.0 st
MiB Mem : 3915.3 total, 247.9 free, 2984.8 used, 985.0 buff/cache
MiB Swap: 256.0 total, 0.0 free, 256.0 used. 930.5 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1056592 mingyuz+ 0 -20 133764 38484 25292 S 18.2 1.0 0:35.55 nxcodec.bin
1 root 20 0 23132 12112 7376 S 0.0 0.3 1:39.97 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.27 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:00.00 pool_workque+
4 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/R-rc+
5 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/R-rc+
6 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/R-sl+
7 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/R-ne+
9 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/0:0H+
12 root 0 -20 0 0 0 I 0.0 0.0 0:00.00 kworker/R-mm+
13 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_tasks_kt+
14 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_tasks_ru+
15 root 20 0 0 0 0 I 0.0 0.0 0:00.00 rcu_tasks_tr+
16 root 20 0 0 0 0 S 0.0 0.0 0:08.00 ksoftirqd/0
17 root 20 0 0 0 0 I 0.0 0.0 30:45.37 rcu_preempt
18 root rt 0 0 0 0 S 0.0 0.0 0:04.93 migration/0
......方法四：使用 journalctl 命令查看系统重启后已运行的时间
4.1 显示 journalctl 命令中系统重启记录的 BOOT ID
$ journalctl --list-boot
IDX BOOT ID FIRST ENTRY LAST ENTRY >
-17 d842be174b26429c84b6c21d8c457ca0 Wed 2024-08-14 10:01:22 CST Wed 2024-08-14>
-16 76b3d204a98d4004809d34add8838c3f Wed 2024-08-14 10:02:14 CST Wed 2024-08-14>
-15 50f754cd41af43119d88d9ca13306d09 Wed 2024-08-14 11:11:42 CST Wed 2024-08-14>
lines 1-19/19 (END)
......（补充：从这里可以看出最后一次系统重启的 BOOT ID 是 d842be174b26429c84b6c21d8c457ca0）
4.2 通过 BOOT ID 显示系统重启的详细信息
$ journalctl -b d842be174b26429c84b6c21d8c457ca0
Aug 14 10:01:22 linux-template kernel: Linux version 6.8.0-35-generic (buildd@lcy02->
Aug 14 10:01:22 linux-template kernel: Command line: BOOT_IMAGE=/boot/vmlinuz-6.8.0->
Aug 14 10:01:22 linux-template kernel: KERNEL supported cpus:
Aug 14 10:01:22 linux-template kernel: Intel GenuineIntel
Aug 14 10:01:22 linux-template kernel: AMD AuthenticAMD
Aug 14 10:01:22 linux-template kernel: Hygon HygonGenuine
Aug 14 10:01:22 linux-template kernel: Centaur CentaurHauls
Aug 14 10:01:22 linux-template kernel: zhaoxin Shanghai
Aug 14 10:01:22 linux-template kernel: BIOS-provided physical RAM map:
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x0000000000000000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x000000000009fc00-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x00000000000f0000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x0000000000100000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x000000007ffd4000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x00000000b0000000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x00000000fed1c000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x00000000feffc000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x00000000fffc0000-0x00000000>
Aug 14 10:01:22 linux-template kernel: BIOS-e820: [mem 0x0000000100000000-0x00000001>
Aug 14 10:01:22 linux-template kernel: NX (Execute Disable) protection: active
Aug 14 10:01:22 linux-template kernel: APIC: Static calls initialized
Aug 14 10:01:22 linux-template kernel: SMBIOS 2.8 present.
......（补充：这里查看的 BOOT ID 是 d842be174b26429c84b6c21d8c457ca0）
参考文献：
https://www.sysgeek.cn/linux-reboot-history
[CONTENT] The network connections required for system register
Content:
RHEL:
| Domain | Port Number | Port protocol |
| subscription.rhsm.redhat.com | 443 | TCP |
| cdn.redhat.com | 443 | TCP |
SLES:
| Domain | Port Number | Port protocol |
| scc.suse.com | 80 or 443 | TCP |
| updates.suse.com | 80 or 443 | TCP |
| installer-updates.suse.com | 80 or 443 | TCP |
Reference:
https://access.redhat.com/solutions/65300
https://www.suse.com/support/kb/doc/?id=000021034#:~:text=%2A%20The%20current%20list%20of%20IPs,for%20scc.suse.com%20and%20registry.suse.com%20are%3A%2099.83.188.102
[步骤] 系统升级 （从 Fedora 39 升级到 Fedora 40）
步骤一：升级所有已安装的软件
# sudo dnf update步骤二：安装 Fedora 升级软件
# sudo dnf install dnf-plugin-system-upgrade步骤三：刷新所有现有版本的软件源
# sudo dnf upgrade --refresh步骤四：下载升级所有所需的软件
# sudo dnf system-upgrade download --releasever=40步骤五：重启并升级系统
# sudo dnf system-upgrade reboot（注意：系统会重启，并在后台升级系统，这个步骤可能会持续很长一段时间，根据虚拟机的硬件性能而定）