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chapter10-18 - Coggle Diagram

- - - - cat / open file and show the text.
      - tr / translate form - to
  - - - -t ----specifies the field delimiter.
      - -k(number) ---option specifies the field number
      - -n ----This option specifies the sort type.
  - - - -w count number of line in file
      - -c count number of byte in file
      - -l count number of line in file
  - - - ^ character is used to ensure that a pattern appears at the beginning of the line
      - The $ must be the last character in the pattern to be effective as an anchor
    - - using grep with the -E option.
        
        +
        
        | like or no pipe
        
        ?
- - - - Peripheral devices are components connected to a computer that allow input, output or data storage. Keyboards, mice, monitors, printers and hard disks are all considered peripherals and are accessed by the system in order to perform functions outside of central processing
      - external devices
    - - Devices connected internally are usually cold-plug,
- - - - host is any device that communicates via a network with another device.
    - - A network is a collection of two or more hosts (computers) that are able to communicate with each other. This communication can be via a wired connection or wireless.
    - - The Internet is an example of a network.
    - - The term Wi-Fi refers to wireless networks
    - - A host that provides a service to another host or client is called a server. For example, a web server stores, processes and delivers web pages. An email server receives incoming mail and delivers outgoing mail.
    - - A feature provided by a host is a service. An example of a service would be when a host provides web pages to another host
    - - A client is a host that is accessing a server. When you are working on a computer surfing the Internet, you are considered to be on a client host.
    - - Also called a gateway, a router is a machine that connects hosts from one network to another network. For example, if you work in an office environment, the computers within the company can all communicate via the local network created by the administrators. To access the Internet, the computers would have to communicate with a router that would be used to forward network communications to the Internet. Typically when you communicate on a large network (like the Internet), several routers are used before your communication reaches its final destination.
  - - - A network packet is used to send network communication between hosts
    - - An Internet Protocol (IP) address is a unique number assigned to a host on a network. Hosts use these numbers to address network communication.
        
        IPv4
        
        IPv6
        
        8-bit refers to numbers from 0 to 255.
    - - Also called a netmask, subnet mask or mask, a network mask is a number system that can be used to define which IP addresses are considered to be within a single network. Because of how routers perform their functions, networks have to be clearly defined.
    - - Each host on a network could have its own hostname because names are more natural for humans to remember than numbers, making it easier for us to address network packets to another host. Hostnames are translated into IP addresses before the network packet is sent on the network.
    - - A Uniform Resource Locator (URL), also commonly called a web address, is used to locate a resource, like a web page, on the internet. It’s what you type into your web browser to access a web page. For example, http://www.netdevgroup.com. It includes the protocol http:// and the hostname www.netdevgroup.com
    - - Hosts can be assigned hostnames, IP addresses and other network-related information by a DHCP (Dynamic Host Configuration Protocol) server. In the world of computers, a protocol is a well-defined set of rules. DHCP defines how network information is assigned to client hosts, and the DHCP server is the machine that provides this information.
    - - As mentioned previously, hostnames are translated into IP addresses, prior to the network packet being sent on the network. So your host needs to know the IP address of all of the other hosts with which you are communicating. When working on a large network (like the Internet), this can pose a challenge as there are so many hosts. A Domain Name System (DNS) provides the service of translating domain names into IP addresses.
    - - In a wired network environment, Ethernet is the most common way to physically connect the hosts into a network. Ethernet cables are connected to network cards that support Ethernet connections. Ethernet cables and devices (such as routers) are specifically designed to support different communication speeds, the lowest being 10 Mbps (10 Megabits per second) and the highest being 100 Gbps (100 gigabits per second). The most common speeds are 100 Mbps and 1 Gbps.
    - - The Transmission Control Protocol/Internet Protocol (TCP/IP) is a fancy name for a collection of protocols (remember, protocol = set of rules) that are used to define how network communication should take place between hosts. While it isn't the only collection of protocols used to define network communication, it is the most often utilized one. As an example, TCP/IP includes the definition of how IP addresses and network masks work.