Advantages of using UNIX with C

• Portability - UNIX, or a variety of UNIX, is available on many machines. Programs written in standard UNIX and C should run on any of them with little difficulty.
• Multiuser / Multitasking - many programs can share a machines processing power.
• File handling - hierarchical file system with many file handling routines.
• Shell Programming - UNIX provides a powerful command interpreter that understands over 200 commands and can also run UNIX and user-defined programs.

• Pipe - where the output of one program can be made the input of another. This can done from command line or within a C program.
• UNIX utilities - there over 200 utilities that let you accomplish many routines without writing new programs. e.g. make, grep, diff, awk, more ....
• System calls - UNIX has about 60 system calls that are at the heart of the operating system or the kernel of UNIX. The calls are actually written in C. All of them can be accessed from C programs. Basic I/0, system clock access are examples. The function open() is an example of a system call.
• Library functions - additions to the operating system.