Sonoma State University

Department of Computer Science

CS-210: Introduction to Unix

Exercise 7

Objective:

Testing one's knowledge of Unix commands in preparation for the midterm exam.

Question 1:

  • Presume the following three text files exist in your home directory on Blue:
    • alpha.txt
    • bravo.txt
    • charlie.txt
  • Using standard output and redirection, what is the syntactically-correct Unix command to merge the contents of alpha.txt, bravo.txt, and charlie.txt into a single file called merged.txt in your home directory. You may NOT safely assume you are currently in your home directory (i.e. you are in some random directory on the Unix system).

Question 2:

  • What is the syntactically-correct Unix command to create an alias "uu" which changes to the parent directory of the parent directory from your current working directory when you type "uu" on the command line? Specifically, I want to be able to go up two directory levels (parent directory of parent directory) with one command.

Question 3:

  • Inside your home directory is the directory My Documents. This directory contains a mixture of directories and files. The files could be one of three possible formats: simple text, Microsoft Word, or Adobe Acrobat. Each file contains an appropriate extension for its file type:
    • Text files have a ".txt" extension (e.g. "simple.txt");
    • Microsoft Word format files contain a ".docx" extension (example: "resume.docx");
    • Adobe Acrobat's portable document format files contain a ".pdf" extension (example: "resume.pdf").
  • What is the syntactically-correct Unix command to locate all text files inside My Documents and all its sub-directories?

Question 4:

  • What is the syntactically-correct Unix command to redirect standard input to a file name myfile.txt in your home directory? You may safely assume myfile.txt does not exist in your home directory.

Question 5:

  • Inside your home directory is a file named secret. What command would you type to change the permissions of the file secret as follows:
    • User permissions: read access, write access, no execute.
    • Group permissions: no read access, no write access, no execute.
    • World permissions: no read access, no write access, no execute.

Question 6:

  • Presume the following five text files exist in your home directory on Blue:
    • recipe1.txt
    • recipe2.txt
    • recipe3.txt
    • recipe4.txt
    • recipe5.txt
  • Using brace expansion and standard output, what is the syntactically-correct Unix command to concatenate these files together into a file called ALL_RECIPES.txt in the following order:
    • recipe5.txt is the first file to be appended to ALL_RECIPES.txt
    • recipe4.txt is the second file to be appended to ALL_RECIPES.txt
    • recipe3.txt is the third file to be appended to ALL_RECIPES.txt
    • recipe2.txt is the fourth file to be appended to ALL_RECIPES.txt
    • recipe1.txt is the fifth file to be appended to ALL_RECIPES.txt

Question 7:

  • A file named mystery is located in your home directory on Blue. What is the syntactically-correct Unix command to determine what type of file mystery is (i.e. image file, text file, sound file, video file, etc.)?

Question 8:

  • What is the syntactically-correct Unix command to search for filenames containing the case-sensitive text, $how me the money! anywhere in the filename in your home directory (and all sub-directories in your home directory on Blue)?

Question 9:

  • A directory named My Documents is located inside your home directory on Blue. Inside My Documents, you need to create the following twelve directories:
    • 2026-01
    • 2026-02
    • 2026-03
    • 2026-04
    • 2026-05
    • 2026-06
    • 2026-07
    • 2026-08
    • 2026-09
    • 2026-10
    • 2026-11
    • 2026-12
  • Using brace expansion, what is the syntactically-correct Unix command to create the directories above inside My Documents?

Question 10:

  • What is the syntactically-correct Unix command to display my user identification number (uid) and group identification number (gid)?

Submission Instructions:

  • Please submit your answers to Canvas for the questions above.