The source code found on pages 145 through 169 of the Computer History Museum's (CHM) "Unix Book II" release contains the assembly listings for the original Unix shell, also known as the Thompson shell. This early command-line interpreter was a fundamental component of the nascent Unix operating system.

These specific pages detail the inner workings of the shell, written in PDP-7 assembly language. The assembly listings, labeled t1 through t8, correspond to different routines and components of the shell program. This provides a fascinating glimpse into the foundational code that established the interactive user experience for which Unix and its successors, like Linux, would become famous.

A Look Inside the Code

The code on these pages, authored by Ken Thompson, showcases the essential features of the first Unix shell, including:

• Command execution: The logic for reading user input, parsing commands and their arguments, and executing programs.
• I/O redirection: The implementation of input and output redirection using the familiar < and > symbols, a groundbreaking feature at the time.
• Shell scripts: The rudimentary beginnings of shell scripting, allowing users to chain commands together in a file for automated execution.

The "Unix Book II" is part of the Dennis M. Ritchie papers collection at the CHM and represents some of the earliest existing Unix source code. The release of this document has been a significant event for computer historians and enthusiasts, offering a direct look at the origins of one of the most influential operating systems ever created.

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That took me about 30 seconds with Google.  Are we doing your homework for you?

-Henry