Programming_Under_Unix_Chapter1 (1).pptx

Programming_Under_Unix_Chapter1 (1).pptx

• 1.
  Programming Under Unix Chapter1: Introduction to UNIX Presented by: [Your Name / Instructor Name] Institution: [Your University Name]
• 2.
  Overview of Chapter1 • Introduction to UNIX • History of UNIX • Command Line Interface (CLI) • Shells (Bash, C Shell) • Distributions & Application Software • File System Structure • Pathnames & File Permissions
• 3.
  Introduction to UNIX •UNIX is a powerful, multiuser, multitasking operating system developed in the 1960s. • Used in servers, workstations, and desktops. • Foundation for many modern OS like Linux, macOS, and Android.
• 4.
  History of UNIX •Developed at AT&T Bell Labs in 1969 by Ken Thompson, Dennis Ritchie, and others. • Rewritten in C in 1973 to enhance portability. • Variants include BSD, System V, and Linux.
• 5.
  UNIX Philosophy • Doone thing and do it well. • Everything is a file. • Use small, modular programs that can be combined.
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  Command Line Interface(CLI) • Primary method to interact with UNIX. • More flexible and powerful than GUI. • Enables script automation and remote access.
• 7.
  Shells in UNIX •Shell: Command interpreter between user and kernel. • Bash (Bourne Again SHell): Default in most Linux distributions. • C Shell (csh): Syntax similar to C programming. • Users can write shell scripts for automation.
• 8.
  Distributions & Application Software •Distributions: OS packages with apps and tools (e.g., Ubuntu, Debian, Fedora). • Application software includes text editors, compilers, browsers. • UNIX applications can run through terminal or GUI.
• 9.
  File System Structure •Hierarchical tree structure. • Root directory: '/' • Common directories: • - /home: user files • - /bin: essential binaries • - /etc: config files • - /usr: user programs
• 10.
  Pathnames in UNIX •Absolute Path: Starts from root (e.g., /home/user/file.txt). • Relative Path: Starts from current directory (e.g., ../file.txt). • Commands: cd, ls, pwd, etc.
• 11.
  File Permissions • Permissiontypes: read (r), write (w), execute (x). • User classes: owner, group, others. • Use 'ls -l' to view permissions. • Change with chmod, chown, chgrp.
• 12.
  File Permission Example •Example: -rwxr-xr-- – Owner: rwx (7), – Group: r-x (5), – Others: r-- (4) • Numeric mode: chmod 754 filename
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  Summary • UNIX isa foundational OS with strong CLI support. • Shells enhance user interaction and automation. • Understanding filesystem and permissions is essential. • Sets the foundation for programming under UNIX.
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  Q&A • Any questionsor clarifications? • Let’s discuss!