OS Assignment

Creating a Custom C Shell to Demonstrate the fork(), exec(), and wait() Calls in a Process and Simulate a shell.

This C shell supports:

• word (internal): Counts the number of words in a file

  Usage: word {-n/d} <filenames>

  • -n: Exempt newline character
  • -d: Find the difference between two files.

• dir (external): Creates a new directory and changes the path into that directory

  Usage: dir {-r|-v} <Directory>

  • -r: If the directory exists, then delete it recursively and create a new one with the same name
  • -v: Print the steps of creation

• date (external): Gets a file's latest modification date

  Usage: date {-R|-d} <filename>

  • -R: Print in RFC5322 format
  • -d: Accept STRING inputs like 'yesterday' and 'tomorrow'

Usage: date -d 'yesterday' <filename>

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