Computer-Science-Workshop

Shell Part 1

Trying out the shell

Basic Navigation and File Operations

  1. Directory Navigation
    • Use pwd to print your current working directory
    • Use ls to list files in the current directory
    • Try ls -l for detailed file information
    • Use cd to change directories
    • Practice using cd .. to go up one directory
    • Use cd ~ to return to your home directory
  2. File and Directory Management
    • Create a new directory called practice using mkdir
    • Create a text file using touch myfile.txt
    • Copy the file using cp myfile.txt myfile_backup.txt
    • Move/rename the file using mv myfile.txt newname.txt
    • Remove a file using rm myfile_backup.txt
    • Remove an empty directory using rmdir
  3. Viewing File Contents
    • Create a file with some text using echo "Hello World" > hello.txt
    • View the file contents using cat hello.txt
    • Use less to view longer files
    • Try head and tail to see the beginning/end of files
  4. Searching for Files
    • Use find to search for files in the current directory
    • Try find . -name "*.txt" to find all .txt files in the current directory
  5. Permissions
    • Use chmod to change file permissions
    • Try chmod +x script.sh to make a script executable
    • The command chmod is used to change the permissions of a file. The +x option adds execute permission to the file. You can change the permissions for different users (owner, group, others) using different combinations of u, g, o, and a.
    • For example, chmod u+x script.sh adds execute permission to the owner of the file.

Practice Exercises

  1. Create a directory structure:
mkdir -p projects

File Permissions Challenge

  1. Create a script that’s not executable e.g. script.sh:
    • Create a simple bash script that prints “Hello, I am a script!”
    • Try to run it
    • Check its current permissions
    • Make it executable
    • Run it again
  2. Permission Practice:
    • Create a directory called secure_files
    • Create some files inside it
    • Remove read permissions from others
    • Remove write permissions from group
    • Practice reading permissions using ls -l

Find Command Challenge

Create a directory structure to practice with, copy the following commands and run them in the terminal:

mkdir -p findme/level1/level2 findme/level1/level3
touch findme/file1.txt
touch findme/level1/file2.txt
touch findme/level1/level2/file3.txt
touch findme/level1/level3/file4.txt
touch findme/level1/level3/script.sh

Your tasks:

  1. Find all .txt files in the findme directory

  2. Find files modified in the last 10 minutes

  3. Zip all files in the findme directory

Hint: Look up how to use find and zip

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