watch – execute a program periodically

commandline session

following commandline session may not be accurate.

$vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 1  0      0 2246368  32720 497284    0    0   217    10  236  436  3  1 92  3
$watch vmstat
$watch -n 0.5 vmstat
$watch -n 0.5 iostat
$watch -n 0.5 iostat
$iostat
Linux 3.12.0 (debian) 	Friday 08 November 2013 	_x86_64_	(2 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           6.64    0.01    2.31    1.80    0.00   89.24

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               8.82       272.09        51.03     696015     130532

$

the following video tutorial content may not be accurate


GNU/Linux Commands for Beginners : alias

this tutorial content may not be accurate

GNU/Linux Terminal – File Permissions! (Chmod, Chown and Chgrp)

this tutorial content may not be accurate

How To Apply a Patch To The Linux Kernel Stable Tree

How Linux is Built

file — determine file type

commandline session

$ls
faq  favicon.ico  index.html  kernel.css  mirrors  pub	robots.txt
$file kernel.css
kernel.css: ASCII text
$file -l | head
Set 0:
Binary patterns:
Text patterns:
Set 1:
Binary patterns:
Text patterns:
Set 0:
Binary patterns:
Strength = 340 : sc68 Atari ST music []
Strength = 340 : T64 tape Image []
$file -l | tail
Strength =  28 : exported SGML document text []
Strength =  20 : Java source [text/x-java]
Strength =  20 : script text executable []
Strength =  18 : a []
Strength =  17 : a []
Strength =  12 : Perl5 module source text []
Strength =   2 : Tcl script []
Set 1:
Binary patterns:
Text patterns:
$



readelf – Displays information about ELF files

commandline session

$readelf  -I /bin/ping

Histogram for `.gnu.hash' bucket list length (total of 3 buckets):
 Length  Number     % of total  Coverage
      0  0          (  0.0%)
      1  0          (  0.0%)      0.0%
      2  0          (  0.0%)      0.0%
      3  3          (100.0%)    100.0%
$readelf  -a /bin/ping | head
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
$readelf  -a /bin/ping | head -n 20
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x402ac0
  Start of program headers:          64 (bytes into file)
  Start of section headers:          38200 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         9
  Size of section headers:           64 (bytes)
  Number of section headers:         27
  Section header string table index: 26
$

hal-device command

output part from "apt-cache show hal"

Description: Hardware Abstraction Layer
 HAL provides an abstract view on hardware.
 .
 This abstraction layer is simply an interface that makes it possible to
 add support for new devices and new ways of connecting devices to the
 computer, without modifying every application that uses the device.
 It maintains a list of devices that currently exist, and can provide
 information about those upon request.
Homepage: http://hal.freedesktop.org/

commandline session

$hal-device > haloutput.txt
$head haloutput.txt
0: udi = '/org/freedesktop/Hal/devices/volume_uuid_c2df0e9b_e267_43d1_87c6_aac360a40320'
  volume.is_mounted = false  (bool)
  volume.linux.is_device_mapper = false  (bool)
  info.product = 'Volume (swap)'  (string)
  volume.is_partition = true  (bool)
  volume.is_disc = false  (bool)
  linux.hotplug_type = 3  (0x3)  (int)
  volume.partition.number = 5  (0x5)  (int)
  volume.block_size = 512  (0x200)  (int)
  info.category = 'volume'  (string)
$tail haloutput.txt
  linux.sysfs_path = '/sys/devices/pci0000:00/0000:00:00.0'  (string)
  info.parent = '/org/freedesktop/Hal/devices/computer'  (string)
  pci.linux.sysfs_path = '/sys/devices/pci0000:00/0000:00:00.0'  (string)
  pci.product_id = 1002  (0x3ea)  (int)
  pci.vendor_id = 4318  (0x10de)  (int)
  pci.subsys_product_id = 20481  (0x5001)  (int)
  pci.subsys_vendor_id = 5208  (0x1458)  (int)
  pci.device_class = 5  (0x5)  (int)
  pci.device_subclass = 0  (0x0)  (int)

$

http://www.freedesktop.org/wiki/Software/hal

Carter, Jimmy: Nomination
[audio:http://www.freeinfosociety.com/media/sounds/141.mp3]