Enabling Network Interface eth0

Login as root and execute the command at the terminal to bring up eth0

ifup eth0

The system would determine an IP address for interface eth0 and return a prompt.
Now, type a command


to view the configuration on a currently active interfaces and the loopback interface. The command is used to configure the kernel-resident network interfaces. If interface name is given as an argument, the details of the that specific interface displayed

ifconfig eth0

Display all interfaces details including disabled interfaces

ifconfig -a

Enable an Interface

ifconfig eth0 up

Disable an Interface

ifconfig eth0 down

Assign IP address to an Interface

ifconfig eth0

Change MTU

ifconfig eth0 mtu XX

The DHCP dynamically assign an IP address to eth0 on the system.

Fedora tested new Linux Network device naming scheme, as implemented by the biosdevname utility provided by Dell. It would give network interfaces names that are both consistent and appropriate to their physical attributes.

who command

who [options] [filename]

To find out the time of last system boot, current run level of the system and list of logged in users and more.


To get the information about currently logged in user on the system which includes login name, terminal line numbers, login time, remote host name

Get the list of users logged in to system

who -u

Details of the current logged in user

who -a

Get system's username


Get user identification information


Get the count of users logged on to system

who -q -H

Get hostname and user associated with standard input such as a keyboard

who -m -H

Display all active processes which are spawned by INIT process

who -p -H

Find status of the user's message as +, – or?

who -T -H

Last boot time of the system

who -b -H

Get the details of all dead processes

who -d -H

System login process details

who -l -H

Current run level of the system

who -r

uptime command

uptime [-options]

To find out how long the system is active or running. It displays the current time, amount of system is in running state, the number of users currently logged, load time for the pat 1, 5 and 15 minutes respectively.

-p, –pretty show uptime in pretty format i.e., human readable format
-h, –help display this help and exit
-s, –since system up since when the system started running
-V, –version output version information and exit

Command w

Get the list of users and their activities


It's a combination of uptime and who commands given one immediately after the other.

top command

top [-b] [-nCOUNT] [-dSECONDS] [-m]

Displays system and processes information as:

  • First Row show: current time, uptime of the machine, users sessions logged in, and average load on the system to the last minute, five minutes and 15 minutes respectively.
  • Second Row: Total Processes running, Running Processes, Sleeping Processes, Stopped Processes, Processes waiting to be stopped from the parent process
  • Third Row : cpu usage percentage(%'s)​ as User processes of CPU, System processes of CPU, Priority upgrade nice of CPU, Percentage of the CPU not used, Processes waiting for I/O operations of CPU, Serving hardware interrupts of CPU, Percentage of the CPU serving software interrupts
  • Fourth and Fifth Row: Memory usage, total memory in use, free, buffers cached.
  • Sixth Row: Processes List running currently. Let’s see what information we can observe in the different columns.

    PID – ID of the process
    USER – The user that is the owner of the process (root)
    PR – priority of the process
    NI – The “NICE” value of the process
    VIRT – virtual memory used by the process
    RES – physical memory used from the process
    SHR – shared memory of the process
    S – indicates the status of the process: S=sleep R=running Z=zombie (S)
    %CPU – This is the percentage of CPU used by this process
    %MEM – This is the percentage of RAM used by the process
    TIME+ –This is the total time of activity of this process
    COMMAND – And this is the name of the process

rsync command

rsync options source destination

For copying and synchronizing files and directories locally as well as remotely. It is used to perform data backups and mirroring between two Linux machines. It copies the whole content of a file or a directory from source to destination and from next time, copies only the changed blocks and bytes to the target.
-v : verbose
-r : copies data recursively (but don’t preserve timestamps and permission while transferring data
-a : archive mode, archive mode allows copying files recursively and it also preserves symbolic links, file permissions, user & group ownerships and timestamps
-z : compress file data
-h : human-readable, output numbers in a human-readable format