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kill -9 process_id(PID) # Forces termination of a process.
(No output unless there is an error, the process is terminated forcefully) |
Analyzing logs and monitoring system activities can help in identifying issues and tracking system performance.
dmesg # allows reviewing messages stored in the Linux ring buffer, providing insights into hardware errors and startup issues. How To Use dmesg
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dmesg -T
[Wed May 29 14:46:00 2024] Run /init as init process
[Wed May 29 14:46:00 2024] with arguments:
[Wed May 29 14:46:00 2024] /init
[Wed May 29 14:46:00 2024] with environment:
[Wed May 29 14:46:00 2024] HOME=/
[Wed May 29 14:46:00 2024] TERM=linux
[Wed May 29 14:46:00 2024] BOOT_IMAGE=/boot/vmlinuz-5.15.0-97-generic
[Wed May 29 14:46:00 2024] biosdevname=0
[Wed May 29 14:46:00 2024] netcfg/do_not_use_netplan=true
[Wed May 29 14:46:00 2024] piix4_smbus 0000:00:01.3: SMBus Host Controller at 0x700, revision 0
[Wed May 29 14:46:00 2024] scsi host2: Virtio SCSI HBA
[Wed May 29 14:46:00 2024] scsi 2:0:0:0: Direct-Access QEMU QEMU HARDDISK 2.5+ PQ: 0 ANSI: 5
[Wed May 29 14:46:00 2024] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input4
[Wed May 29 14:46:00 2024] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input3
[Wed May 29 14:46:00 2024] cryptd: max_cpu_qlen set to 1000 |
journalctl # Views systemd logs and allows filtering Linux system logs to extract relevant information for monitoring and troubleshooting. How To Use journalctl
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journalctl
-- Logs begin at Tue 2024-06-18 10:55:23 UTC, end at Tue 2024-06-18 12:06:19 UTC. --
Jun 18 10:55:23 hostname kernel: Linux version 5.4.0-74-generic (buildd@lcy01-amd64-013) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #83-Ubuntu SMP Thu May 6 10:34:06 UTC 2021 (Ubuntu 5.4.0-74.83-generic 5.4.101)
Jun 18 10:55:23 hostname kernel: Command line: BOOT_IMAGE=/boot/vmlinuz-5.4.0-74-generic root=UUID=5d7f5dcd-1234-5678-9abc-def012345678 ro quiet splash vt.handoff=7
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journalctl -u service_name # Views Logs for a Specific Service
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journalctl -u apache2
-- Logs begin at Tue 2024-06-18 10:55:23 UTC, end at Tue 2024-06-18 12:05:19 UTC. --
Jun 18 11:56:19 hostname systemd[1]: Starting The Apache HTTP Server...
Jun 18 11:56:19 hostname apache2[1342]: AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message
Jun 18 11:56:19 hostname systemd[1]: Started The Apache HTTP Server dmesg # Prints kernel ring buffer messages.
journalctl # Views systemd logs.
journalctl -u service_name # Views logs for a specific service.
tail -f /var/log/syslog # Continuously displays system log updates.
sar # Collects, reports, and saves system activity information (requires sysstat).
uptime # Shows how long the system has been running and load averages. |