运行命令：
[root@east81 Desktop]# dmesg|grep usb
[0.211798] usbcore: registered new interface driver usbfs
[0.211801] usbcore: registered new interface driver hub
[0.211812] usbcore: registered new device driver usb
[0.513302] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
[0.513303] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[0.513304] usb usb1: Product: xHCI Host Controller
[0.513304] usb usb1: Manufacturer: Linux 3.10.0-327.el7.x86_64 xhci-hcd
[0.513305] usb usb1: SerialNumber: 0000:00:14.0
[0.518700] usb usb2: New USB device found, idVendor=1d6b, idProduct=0003
[0.518701] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[0.518702] usb usb2: Product: xHCI Host Controller
[0.518702] usb usb2: Manufacturer: Linux 3.10.0-327.el7.x86_64 xhci-hcd
[0.518703] usb usb2: SerialNumber: 0000:00:14.0
[0.525247] usbcore: registered new interface driver usbserial
[0.525249] usbcore: registered new interface driver usbserial_generic
[0.525252] usbserial: USB Serial support registered for generic
[0.529231] usbcore: registered new interface driver usbhid
[0.529232] usbhid: USB HID core driver
[0.870736] usb 1-4: new low-speed USB device number 2 using xhci_hcd
[1.040346] usb 1-4: New USB device found, idVendor=413c, idProduct=301a
[1.040348] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[1.040350] usb 1-4: Product: Dell MS116 USB Optical Mouse
[1.040350] usb 1-4: Manufacturer: PixArt
[1.040536] usb 1-4: ep 0x81 - rounding interval to 64 microframes, ep desc says 80 microframes
[1.042664] input: PixArt Dell MS116 USB Optical Mouse as /devices/pci0000:00/0000:00:14.0/usb1/1-4/1-4:1.0/input/input3
[1.043039] hid-generic 0003:413C:301A.0001: input,hidraw0: USB HID v1.11 Mouse [PixArt Dell MS116 USB Optical Mouse] on usb-0000:00:14.0-4/input0
[1.196265] usb 1-5: new low-speed USB device number 3 using xhci_hcd
[1.367920] usb 1-5: New USB device found, idVendor=413c, idProduct=2113
[1.367922] usb 1-5: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[1.367923] usb 1-5: Product: Dell KB216 Wired Keyboard
[1.368111] usb 1-5: ep 0x81 - rounding interval to 128 microframes, ep desc says 192 microframes
[1.368113] usb 1-5: ep 0x82 - rounding interval to 256 microframes, ep desc says 384 microframes
[1.372549] input: Dell KB216 Wired Keyboard as /devices/pci0000:00/0000:00:14.0/usb1/1-5/1-5:1.0/input/input4
[1.423970] hid-generic 0003:413C:2113.0002: input,hidraw1: USB HID v1.11 Keyboard [Dell KB216 Wired Keyboard] on usb-0000:00:14.0-5/input0
[1.429641] input: Dell KB216 Wired Keyboard as /devices/pci0000:00/0000:00:14.0/usb1/1-5/1-5:1.1/input/input5
[1.480682] hid-generic 0003:413C:2113.0003: input,hidraw2: USB HID v1.11 Device [Dell KB216 Wired Keyboard] on usb-0000:00:14.0-5/input1
[root@east81 Desktop]# dmesg -c
这样就可以全部清空记录了。