Linux Basics(1 of 6)

Linux Basics(1 of 6):

UNIX Standards:

BSD
SYSTEM V (system 5)

BSD:
Free BSD
Open BSD
Net BSD

SYSTEM V:

Solaris (Developed by SUN Microsystems)
HP-UX (Developed by HP)
SCO

There are some UNIX versions that folow some good features from BSD standard and some from
System v standard they can be named as Hybrid Unix Like:

LINUX
AIX

FILE TYPES IN LINUX:

In Linux/Unix every thing is treated as a file and every thing is represented by a file. Even devices
are represented by device files. There are four types files in Linux/Unix

1. Normal File:
Every file that contains data in it is caled normal file. E.g. execute able files,
Text files, movie files, audio files and Virus files etc.etc.

2. Directory File:
These are container files that hold other file and directories.

3. Link File :
These are like short cuts in windows. These just point towards the actual file.

4. Device File:
These represent devices. When ever we need to access a device we use these
files and these files gets the job done for us. These are present in /dev
directories.

THREE ROOTs IN LINUX/UNIX:

Word root is used for three entities in Linux/Unix

root user: Admin user of Unix/Linux systems is root user.
/root directory: Home directory of root user.
/: / is like my computer in Windows. It is the parent directory of al linux system.
Every thing is present under this directory

Note: Linux/Unix is case sensitive in every thing from username and password to parameters of file and command options.