Day 02: Ownership, Process Control & Disk/Network Telemetry

Day 02 · Lunch — Ownership, Process Control & Disk/Network Telemetry

⚡ 60-Second Mental Model (Student Digest)

╔══════════════════════════════════════════════════════════════════════════════╗
║  ZOTHOS × 1NC0GN30 // LINUX FILESYSTEM & SHELL EXECUTION ARCHITECTURE       ║
╠══════════════════════════════════════════════════════════════════════════════╣
║                                                                              ║
║   [ USER TERMINAL / TUI ]  ──( stdin 0 )──►  [ BASH / ZSH SHELL PARSER ]     ║
║                                                       │                      ║
║                                              ( glibc / syscalls )            ║
║                                                       ▼                      ║
║   [ VFS / INODE TABLE ]    ◄───────────────  [ LINUX KERNEL RING 0 ]         ║
║     ├── /bin  (Core Binaries)                  ├── Process Scheduler         ║
║     ├── /etc  (System Configs)                 ├── Memory Manager            ║
║     ├── /home (Operator Workspaces)            └── Netfilter / I/O           ║
║     └── /var  (Logs & Runtime State)                                         ║
╚══════════════════════════════════════════════════════════════════════════════╝

---

Welcome to Day 2's lunch study guide! This guide covers file compression and archiving, disk management, and network utilities. Use this guide to review and reinforce your understanding of the commands introduced in the Day 2 lunch challenge.

File Compression and Archiving

tar

The tar command is used to create and extract archives. It can also compress files using various compression algorithms.

Examples:
```sh
tar -cvf archive.tar file1.txt file2.txt # Create an archive named 'archive.tar' with 'file1.txt' and 'file2.txt'
tar -xvf archive.tar # Extract the contents of 'archive.tar'
tar -czvf archive.tar.gz file1.txt file2.txt # Create a compressed archive with gzip
tar -xzvf archive.tar.gz # Extract a compressed archive with gzip
tar -cf archive.tar -C /path/to/directory/ . # Create an archive of all files in '/path/to/directory/'
tar -tf archive.tar # List the contents of 'archive.tar'

Description:

-c creates a new archive.
-x extracts an archive.
-v displays verbose output (shows the progress).
-f specifies the filename of the archive.
-z compresses the archive using gzip.
-j uses bzip2 compression (not used in these examples but is an option).
-C changes to the directory before adding files to the archive.
-t lists the contents of the archive.

Disk Usage and Management
df

The df command reports disk space usage.

Examples:

sh

df -h # Show disk space usage in human-readable format
df -T # Show the file system type along with disk usage

Description:

-h displays sizes in human-readable format (e.g., GB, MB).
-T shows the file system type.

fdisk

The fdisk command is used for disk partitioning.

Examples:

sh

sudo fdisk -l # List all disk partitions and their sizes
sudo fdisk /dev/sda # Open the fdisk utility for disk '/dev/sda'

Description:

-l lists all partitions.
/dev/sda is an example of a disk device; replace with your actual device name.

du

The du command provides disk usage information.

Examples:

sh

du -sh directory/ # Show the total disk usage of 'directory/' in a human-readable format
du -a # Show disk usage of all files and directories recursively
du -ch | grep total # Show disk usage and find the total size
du -sh --max-depth=1 # Show disk usage of directories within 'directory/' up to 1 level deep

Description:

-s summarizes the total usage.
-h displays sizes in human-readable format.
--max-depth limits the depth of directory recursion.

Network Utilities
netstat

The netstat command displays network connections, routing tables, and network interface statistics.

Examples:

sh

netstat -tuln # Show all listening TCP and UDP ports
netstat -r # Show the routing table

Description:

-t shows TCP connections.
-u shows UDP connections.
-l shows only listening sockets.
-n displays addresses and port numbers numerically.

ping

The ping command tests connectivity to a network host.

Examples:

sh

ping google.com # Test connectivity to 'google.com'
ping -c 4 google.com # Ping 'google.com' 4 times

Description:

-c specifies the number of packets to send.

traceroute

The traceroute command shows the route packets take to a network host.

Examples:

sh

traceroute google.com # Trace the route to 'google.com'
traceroute -n google.com # Trace the route without resolving hostnames

Description:

-n displays numerical addresses instead of resolving hostnames.

Summary

File Compression and Archiving: tar helps in creating and extracting compressed archives.
Disk Usage and Management: df and du provide disk usage information, while fdisk is used for partition management.
Network Utilities: netstat, ping, and traceroute are used to monitor network connections and troubleshoot network issues.

Review these commands and practice using them in your terminal to reinforce your understanding. Good luck with your studies!

Day 02 · Dinner — Ownership, Process Control & Disk/Network Telemetry

⚡ 60-Second Mental Model (Student Digest)

╔══════════════════════════════════════════════════════════════════════════════╗
║  ZOTHOS × 1NC0GN30 // LINUX FILESYSTEM & SHELL EXECUTION ARCHITECTURE       ║
╠══════════════════════════════════════════════════════════════════════════════╣
║                                                                              ║
║   [ USER TERMINAL / TUI ]  ──( stdin 0 )──►  [ BASH / ZSH SHELL PARSER ]     ║
║                                                       │                      ║
║                                              ( glibc / syscalls )            ║
║                                                       ▼                      ║
║   [ VFS / INODE TABLE ]    ◄───────────────  [ LINUX KERNEL RING 0 ]         ║
║     ├── /bin  (Core Binaries)                  ├── Process Scheduler         ║
║     ├── /etc  (System Configs)                 ├── Memory Manager            ║
║     ├── /home (Operator Workspaces)            └── Netfilter / I/O           ║
║     └── /var  (Logs & Runtime State)                                         ║
╚══════════════════════════════════════════════════════════════════════════════╝

---

Overview

In this dinner session, we've reviewed and expanded on the commands and concepts from Day 1 and Day 2, including new advanced topics. This study guide consolidates all the important commands and their advanced options for a thorough understanding.

---

1. ls - Listing Directory Contents

Description: Lists files and directories in the specified directory.

Common Options:

- -l: Detailed listing (permissions, owner, size, modification date).
- -a: List all files, including hidden ones (those starting with a dot).
- -R: Recursively list all subdirectories.
- --color=auto: Color-code output for better readability.

Examples:

```bash
ls
ls -l
ls -a
ls -lh
ls -R
ls --color=auto

2. cd - Changing Directories

Description: Changes the current working directory.
Common Options:
..: Move up one directory.
~: Change to the home directory.
-: Switch to the previous directory.
Examples:

bash

cd /home/user
cd ..
cd ~
cd -
cd /

3. touch - Creating and Updating Files

Description: Creates a new empty file or updates the timestamp of an existing file.
Common Options:
-c: Do not create files; only update existing ones.
-t: Set a specific timestamp.
Examples:

bash

touch newfile.txt
touch existingfile.txt
touch file1.txt file2.txt
touch -c non_existing_file.txt
touch -t 202407292030.00 file.txt

4. rm - Removing Files

Description: Removes files or directories. The operation is irreversible.
Common Options:
-i: Prompt before deleting each file.
-r: Recursively remove directories and their contents.
-f: Force removal without prompting.
Examples:

bash

rm file.txt
rm -i file.txt
rm -r directory/
rm -f file.txt
rm -rf directory/

5. pwd - Printing Working Directory

Description: Prints the full path of the current working directory.
Common Options:
-L: Logical path (resolves symbolic links).
-P: Physical path (does not resolve symbolic links).
Examples:

bash

pwd
pwd -L
pwd -P

6. mkdir - Creating Directories

Description: Creates a new directory or directories.
Common Options:
-p: Create parent directories as needed.
-m: Set directory permissions.
Examples:

bash

mkdir new_directory
mkdir -p parent/child
mkdir -m 755 new_dir

7. cp - Copying Files and Directories

Description: Copies files or directories from one location to another.
Common Options:
-r: Recursively copy directories.
-i: Prompt before overwriting files.
-a: Archive mode; preserves attributes and copies recursively.
Examples:

bash

cp file1.txt file2.txt
cp -r dir1/ dir2/
cp -i file.txt backup/
cp -u file1.txt destination/
cp -a source/ destination/

8. mv - Moving and Renaming Files

Description: Moves or renames files and directories.
Common Options:
-i: Prompt before overwriting files.
-u: Move only if the source file is newer.
Examples:

bash

mv file1.txt /path/to/destination/
mv oldname.txt newname.txt
mv -i file1.txt backup/
mv -u file1.txt destination/

9. cat - Viewing File Contents

Description: Displays the contents of files. Can concatenate multiple files.
Common Options:
>: Redirect output to a file.
| less: View file contents page by page.
Examples:

bash

cat file.txt
cat file1.txt file2.txt
cat file.txt > newfile.txt
cat file.txt | less

10. chmod - Changing File Permissions

Description: Changes the permissions of files and directories.
Common Options:
Numeric (e.g., 755): Set permissions using octal notation.
Symbolic (e.g., u+x): Add or remove permissions using symbols.
Examples:

bash

chmod 755 script.sh
chmod u+x script.sh
chmod go-rwx file.txt
chmod 644 file.txt

11. du - Displaying Disk Usage

Description: Shows disk usage of files and directories.
Common Options:
-sh: Human-readable summary.
-a: Show all files and directories.
--max-depth: Limit depth of directory traversal.
Examples:

bash

du -sh directory/
du -a
du -ch | grep total
du -sh --max-depth=1

12. netstat - Network Statistics

Description: Displays network connections, routing tables, and network statistics.
Common Options:
-tuln: Show active listening ports and associated network services.
-r: Display the routing table.
Examples:

bash

netstat -tuln
netstat -r

13. ping - Testing Connectivity

Description: Sends ICMP ECHO_REQUEST packets to test connectivity to a host.
Common Options:
-c: Specify the number of packets to send.
Examples:

bash

ping example.com
ping -c 5 example.com

14. traceroute - Tracing Route

Description: Traces the route packets take to a destination.
Common Options:
-I: Use ICMP ECHO_REQUEST instead of UDP packets.
Examples:

bash

traceroute example.com
traceroute -I example.com

15. Advanced File Operations

Description: Involves advanced tools for searching and processing text.
Commands:
find: Searches for files in a directory hierarchy.
grep: Searches for patterns within files.
sed: Stream editor for text transformations.
awk: Text processing language.
Examples:

bash

find /path/to/search -name 'file.txt'
grep 'search_term' file.txt
sed 's/old/new/g' file.txt
awk '{print $1}' file.txt
find . -type f -exec grep 'pattern' {} +

Summary: This guide covers basic and advanced file and directory management commands, including viewing, copying, moving, and removing files, as well as networking and advanced text processing commands. Mastery of these tools will enhance your efficiency in managing and analyzing data on Unix/Linux systems.

Feel free to review these commands and practice them to strengthen your command-line skills!