Reference of linux proc file system - http://www.coolcoder.in/2014/01/the-power-of-proc-file-system-in-linux.html

Power save tool - http://www.ubuntugeek.com/laptop-mode-tools-laptop-power-saving-package-for-linux-systems.html

Disk usage report - http://www.ubuntugeek.com/hard-disk-usage-and-availability-report-tools.html

USB info at /var/log/messages

Oct 20 03:56:14 carfield kernel: [ 3568.521099] usb 1-6: configuration #1 chosen from 1 choice
Oct 20 03:56:14 carfield kernel: [ 3568.557038] Initializing USB Mass Storage driver...
Oct 20 03:56:14 carfield kernel: [ 3568.557228] scsi4 : SCSI emulation for USB Mass Storage devices
Oct 20 03:56:14 carfield kernel: [ 3568.557407] usbcore: registered new interface driver usb-storage
Oct 20 03:56:14 carfield kernel: [ 3568.557429] USB Mass Storage support registered.
Oct 20 03:56:19 carfield kernel: [ 3573.557428] scsi 4:0:0:0: Direct-Access     BUFFALO  USB Flash Disk   4000 PQ: 0 ANSI: 0 CCS
Oct 20 03:56:19 carfield kernel: [ 3573.559904] sd 4:0:0:0: [sdc] 7864320 512-byte hardware sectors: (4.02 GB/3.75 GiB)
Oct 20 03:56:19 carfield kernel: [ 3573.560766] sd 4:0:0:0: [sdc] Write Protect is off
Oct 20 03:56:19 carfield kernel: [ 3573.562913] sd 4:0:0:0: [sdc] 7864320 512-byte hardware sectors: (4.02 GB/3.75 GiB)
Oct 20 03:56:19 carfield kernel: [ 3573.563765] sd 4:0:0:0: [sdc] Write Protect is off
Oct 20 03:56:19 carfield kernel: [ 3573.563772]  sdc: sdc1