Category: *nix

Red_Hat_ANZ_Cloud_Adoption_Index_FINAL

• Best Pratices for *inux
  • DMZ – FreeBSD
  • Server – CentOS
  • Desktop – Ubuntu
• Mount NFS
  • create folder mnt/nfsmount
  • chmod -R 777 mnt /nfsmount
  • mount -t nfs server:/vol/share /mnt/nfsmount/
  • touch /mnt/nfsmount
  • umount /mnt/nfsmount
  • cat /etc/fstab (NFSServer:/dir /mnt nfs defaults 0 0)
• Check if OS is 32 or 64 Bit
  • getconf LONG_BIT
    
• Reset Root Password
  • At boot press F2 to access GRUB
  • Select KERNEL and Press E to edit
  • type single at the end of the line ENTER
  • Select KERNEL and Press B
  • type passwd at prompt and change the password
• Enable Superuser Root account

sudo – means superuser do

$sudo passwd root

• Disable root account

$sudo passwd -l root

• Work on a root console

$sudo -i

• Remove entering password for sudo

$sudo visudo

%admin ALL=NOPASSWD: ALL

• Excute .sh script

sh file.sh

chmod +x file.sh

./file.sh

• System Reboots and Shutdowns

sudo reboot

sudo shutdown -h 0

halt

• Mount and Unmount

sudo umount /media/CDROM/ << check Capital Letters

mount /media/CDROM/

• ifconfig

• Get Linux and Distro Version

cat /etc/*-release

cat /etc/issue

uname -r

• Edit NIC Configuration

– /etc/sysconfig/networking/devices/ifcfg-eth0

– /etc/network/interfaces (ubuntu)

– /etc/sysconfig/network-scripts/ifcfg-ethX (CentOS, XenServer, RedHat, OLE)

• Change Hostname

– /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=hostname.com

– nano /etc/hosts

10.0.0.1 hostname.com hostname

127.0.0.1 localhost.localdomain localhost

– sysctl kernel.hostname=NEW_HOSTNAME

– grep -r -l $( hostname)

– vi $( grep -r -l $(hostname) . )

– sudo find /etc/ -type f -exec sed -i ‘s/old_hostname/new_hostname/g’ {} \;

– sudo find /etc -type f -exec grep old_hostname {} \;

– hostname -v yourhostname

– system-config-network

– “newhostname” > /proc/sys/kernel/hostname

• Static IP Address Format

ifconfig add eth0 192.168.63.129

DEVICE=eth0BOOTPROTO=noneONBOOT=yesNETMASK=255.255.255.0IPADDR=10.0.0.9

iface eth0 inet static
address 192.168.1.10
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.1

• Renew IP Address

$sudo dhclient -r

# ifdown eth0
# ifup eth0
# /etc/init.d/network restart

• Enable DHCP

/etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=”eth0″
HWADDR=”5A:7B:9B:44:64:00″
NM_CONTROLLED=”yes”
ONBOOT=”yes”
BOOTPROTO=”dhcp”
DHCP_HOSTNAME=”hostname”

• Edit Firewall (IPtables)
• Set Static IP on XenServer
  • Edit the file /etc/sysconfig/network-scripts/ifcfg-eth0 and change: BOOTPROTO=dhcpto:BOOTPROTO=none
  • In the file /etc/sysconfig/network-scripts/ifcfg-xenbr0, enter the following parameters, then save the file:IPADDR=<static ip of XenServer Host>NETMASK=<netmask value>GATEWAY=<gateway ip>
• Mount CD-ROM
  • mount /dev/hdc /mnt/cdrom
  • ls /mnt/cdrom
• Check Diskspace
  • Df –h check diskspace
• Find file
  • find {/path/to/directory/} -type f -size +{size-in-kb}k -exec ls -lh {} \; | awk ‘{ print $9 “: ” $5 }’         
• Unload and load the HBA driver which will cause it to rescan the SCSI devices: 

• • modprobe -r <hba-driver-module> 
  • modprobe <hba-driver-module> 

• IRC
  • /msg nickserv register PASSWORD EMAIL
  • /msg nickserv identify PASSWORD
• Storage Commands
  • vgscan
  • lvscan
  • pvscan
  • fdisk -l
  • multipath -ll
• Show open files
  • lsof
• Show hardware info
  • dmidecode
• Display continuous clock for 1000 seconds
• [source]repeat 1000 sh -c ‘( clear ; date +” %H.%M.%S” | xargs banner ; sleep 1)'[/source]
• DU
• Watch Startwars
  • telnet towel.blinkenlights.nl
• Compile from source
  • tar xzf htop-2.2.0.tar.gz
  • cd htop-2.2.0
  • ./configure
  • make
  • sudo make install
  • sudo make uninstall

whoami
cd `
w
ls -a
pwd
last 
uptime
sudo rpm -i htop-2.2.0-3.el7.x86_64.rpm
sudo rpm -e htop
sudo dpkg -i htop_2.0.2-1_amd64.deb
sudo dpkg --remove htop
apt-get
yum install
cat /etc/*release*
cat /etc/*issue*
lsb_release -a
hostnamectl
ldd filename (Check dependencies)