1. Redhat Linux : RHCE 6
UNIX Developed in 1973 by Dennis Ritchie and Kennth Welsh
Features of Unix:
1. Multi taskiing
2. Multi user capability
3. Security (System level-Users & pwds, File level- rwx)
4. Portability(HW independent)
5. Help
6. Open source code
UNIX Flavours:
UNIX - UNIX - UFS (Unix Filesystem)
SunSolaris - Sun Micro Systems -> Oracle - ZFS (Zeta Filesystem)
IBM - IBM AIX - JFS (Journalized FS)
HPUX - HP Unix - HPFS (High Performance FS)
Redhat - RHEL - ext2, ext3, ext4 Filesystems
Redhat Linux:
Linux flavours:
1. Fedora
2. Debian
3. Ubuntu
4. CentOS
5. MacOS
Certifications:
RHCSA - 2.5 Hrs 210 outof 300 for pass
RHCE - 2 Hrs 210 outof 300 for pass
Intoduction to Linux
Basic Commands:
pwd : present working directory
hostname
whoami
who am i
tty(terminal type)
who
uname -a
cd
echo $0 : display the current shell
csh
bash
cat /etc/shells
cp /etc/passwd /tmp/passwd
grep --color root /tmp/passwd : highlights 'root'
grep ^root /tmp/passwd : line starts with root
grep /bin/bash$ /tmp/passwd : line end with /bin/bash
grep -v /bin/bash$ /tmp/passwd : line which doesnot end with /bin/bash
grep -c /bin/bash$ /tmp/passwd : count the lines ending with /bin/bash
grep -n /bin/bash$ /tmp/passwd : give the line number
cut -c 1-4 filename : cut first 4 characters from each line
cut -d: -f1,2,3 filename : cut the first three fields of the content
tr : translates lower case to upper or viceversa
head : display first n lines
tail : display last n lines
more : open a page without up/down arrows
less : open a page with up/down arrows
find : find files or folders
sort -u filename : sort in alphabetical order
sort
find . -atime +1 : find by time
find . -name *.* : find by name
find . -size +1024c
who | tee lsout : tee outputs to file and screen
grep -v ^$ : to display all lines except blank lines
touch test{1..100} : to create test1 - test100 files
* 64 GUI terminals are possible in Linux 6.4
* GUI terminals are called pts(psuedo terminals)
* CLI terminals from F1 to F6 are called tty
Installation:
Stand alone - CD/DVD
Newtwork - Using network(Image from a storage server)
ks.cfg - kickstart configuration used for automate installation in many servers from storage server.
(Solaris it is called jumpstart)
Stand ALone:
Partitions:
/ - root (min 8 GB)
/boot - boot files (min 100mb)
swap - virtual memory(doubl the ram upto a limit)
* NTP - Network Type Protocol. Used for time synchronization. 3 NTPs all over the world.
* PXE - should be enabled for network installation
* SCSI, CATA, PATA, SATA, IDE(Intergrated Device Envt)
IDE - hda, hdb(hd)
SCSI, SATA, ATA - sda, sdb(sd)
* bootloader will be installed in /boot
* pre-installation and post installation (before and after removing installation media)
* kdump is used for kernel recovery and is sored in /boot
Linux System Structure:
1. Hardware
2. Kernel
3. Shell
4. Users
Types of shells:
sh shell - bourne shell
bash shell - bourne again shell(Default shell in Linux)
ksh shell
csh shell
tcsh shell
nologin shell
zsh shell
Features of bash shell:
tab completion
# for root
$ normal user
Kernel Functions include:
Job scheduling
Process management
Memory management
Network Managemnt
GNOME - GNU Object Model Envt
* Kernal is the hard core of the OS
* 32 and 64 kernels are available
* Shell are of login shell and no-login shell
* /etc/shells : contains shells installed
* echo $0 gives the shell logged in
* you can change from any shell to any other shell
* /etc/profiles stores profile details(aliases can be done here)
* /etc/bashrc for all users and .bashrc for normal users.
