The features of the UNIX operating system are:- 

1. Multi-tasking:

More than one program can be run at a time

2. Portability:

Only the kernel (<10%) is written in assembler tools for program development a wide range of support tools (debuggers, compilers). The system is written in high-level language making it easier to read, understand, changed and, therefore move to other machines.

3. Machine-independence: 

The System hides the machine architecture from the user, making it easier to write applications that can run on micros, mins, and mainframes.

4. Multi-User Operations:

UNIX is a multi-user system designed to support a group of users simultaneously. The system allows for the sharing of processing power and peripheral resources, while at the same time providing excellent security features.

5. Hierarchical File System:

UNIX uses a hierarchical file structure to store information. This structure has the maximum flexibility in grouping information in a way that reflects its natural state. It allows for easy maintenance and efficient implementation.