!sysadmin
@lemmy.mlcross-posted from: https://lemmy.run/post/10044
Beginner's Guide to nc (Netcat)
Welcome to the beginner's guide to nc (Netcat)! Netcat is a versatile networking utility that allows you to read from and write to network connections using TCP or UDP. It's a powerful tool for network troubleshooting, port scanning, file transfer, and even creating simple network servers. In this guide, we'll cover the basics of nc and how to use it effectively.
Installation
To use nc, you first need to install it on your system. The installation process may vary depending on your operating system. Here are a few common methods:
Linux
On most Linux distributions, nc is usually included by default. If it's not installed, you can install it using your package manager. For example, on Ubuntu or Debian, open a terminal and run:
sudo apt-get install netcat
macOS
macOS doesn't come with nc pre-installed, but you can easily install it using the Homebrew package manager. Open a terminal and run:
brew install netcat
Windows
For Windows users, you can download the official version of nc from the Nmap project's website. Choose the appropriate installer for your system and follow the installation instructions.
Basic Usage
Once you have nc installed, you can start using it to interact with network connections. Here are a few common use cases:
Connect to a Server
To connect to a server using nc, you need to know the server's IP address or domain name and the port number it's listening on. Use the following command:
nc <host> <port>
For example, to connect to a web server running on
example.com
on port80
, you would run:nc example.com 80
Send and Receive Data
After establishing a connection, you can send and receive data through nc. Anything you type will be sent to the server, and any response from the server will be displayed on your screen. Simply type your message and press Enter.
File Transfer
nc can also be used for simple file transfer between two machines. One machine acts as the server and the other as the client. On the receiving machine (server), run the following command:
nc -l <port> > output_file
On the sending machine (client), use the following command to send a file:
nc <server_ip> <port> < input_file
The receiving machine will save the file as
output_file
. Make sure to replace<port>
,<server_ip>
,input_file
, andoutput_file
with the appropriate values.Port Scanning
Another useful feature of nc is port scanning. It allows you to check if a particular port on a remote machine is open or closed. Use the following command:
nc -z <host> <start_port>-<end_port>
For example, to scan ports
1
to100
onexample.com
, run:nc -z example.com 1-100
Conclusion
Congratulations! You've learned the basics of nc and how to use it for various network-related tasks. This guide only scratches the surface of nc's capabilities, so feel free to explore more advanced features and options in the official documentation or online resources. Happy networking!
cross-posted from: https://lemmy.run/post/8710
Beginner's Guide to
htop
Introduction
htop
is an interactive process viewer and system monitor for Linux systems. It provides a real-time overview of your system's processes, resource usage, and other vital system information. This guide will help you get started withhtop
and understand its various features.Installation
We are assuming that you are using ubuntu or debain based distros here.
To install
htop
, follow these steps:
- Open the terminal.
- Update the package list by running the command:
sudo apt update
.- Install
htop
by running the command:sudo apt install htop
.- Enter your password when prompted.
- Wait for the installation to complete.
Launching
htop
Once
htop
is installed, you can launch it by following these steps:
- Open the terminal.
- Type
htop
and press Enter.Understanding the
htop
InterfaceAfter launching
htop
, you'll see the following information on your screen:
- A header displaying the system's uptime, load average, and total number of tasks.
- A list of processes, each represented by a row.
- A footer showing various system-related information.
Navigating
htop
htop
provides several keyboard shortcuts for navigating and interacting with the interface. Here are some common shortcuts:
- Arrow keys: Move the cursor up and down the process list.
- Enter: Expand or collapse a process to show or hide its children.
- Space: Tag or untag a process.
- F1: Display the help screen with a list of available shortcuts.
- F2: Change the setup options, such as columns displayed and sorting methods.
- F3: Search for a specific process by name.
- F4: Filter the process list by process owner.
- F5: Tree view - display the process hierarchy as a tree.
- F6: Sort the process list by different columns, such as CPU usage or memory.
- F9: Send a signal to a selected process, such as terminating it.
- F10: Quit
htop
and exit the program.Customizing
htop
htop
allows you to customize its appearance and behavior. You can modify settings such as colors, columns displayed, and more. To access the setup menu, press the F2 key. Here are a few options you can modify:
- Columns: Select which columns to display in the process list.
- Colors: Customize the color scheme used by
htop
.- Meters: Choose which system meters to display in the header and footer.
- Sorting: Set the default sorting method for the process list.
Exiting
htop
To exit
htop
and return to the terminal, press the F10 key or simply close the terminal window.Conclusion
Congratulations! You now have a basic understanding of how to use
htop
on the Linux bash terminal. Withhtop
, you can efficiently monitor system processes, resource usage, and gain valuable insights into your Linux system. Explore the various features and options available inhtop
to get the most out of this powerful tool.Remember, you can always refer to the built-in help screen (F1) for a complete list of available shortcuts and commands.
Enjoy using
htop
and happy monitoring!
cross-posted from: https://lemmy.run/post/9328
Introduction to
awk
:
awk
is a powerful text processing tool that allows you to manipulate structured data and perform various operations on it. It uses a simple pattern-action paradigm, where you define patterns to match and corresponding actions to be performed.Basic Syntax:
The basic syntax of
awk
is as follows:awk 'pattern { action }' input_file
The pattern specifies the conditions that must be met for the action to be performed.
The action specifies the operations to be carried out when the pattern is matched.
The input_file is the file on which you want to perform the
awk
operation. If not specified,awk
reads from standard input.Printing Lines:
To start with, let's see how to print lines in Markdown using
awk
. Suppose you have a Markdown file namedinput.md
.
- To print all lines, use the following command:
awk '{ print }' input.md
- To print lines that match a specific pattern, use:
awk '/pattern/ { print }' input.md
Field Separation:
By default,
awk
treats each line as a sequence of fields separated by whitespace. You can access and manipulate these fields using the$
symbol.
- To print the first field of each line, use:
awk '{ print $1 }' input.md
Conditional Statements:
awk
allows you to perform conditional operations usingif
statements.
- To print lines where a specific field matches a condition, use:
awk '$2 == "value" { print }' input.md
Editing Markdown Files:
Markdown files often contain structured elements such as headings, lists, and links. You can use
awk
to modify and manipulate these elements.
- To change all occurrences of a specific word, use the
gsub
function:awk '{ gsub("old_word", "new_word"); print }' input.md
Saving Output:
By default,
awk
prints the result on the console. If you want to save it to a file, use the redirection operator (>
).
- To save the output to a file, use:
awk '{ print }' input.md > output.md
Further Learning:
This guide provides a basic introduction to using
awk
for text manipulation in Markdown. To learn more advanced features and techniques, refer to theawk
documentation and explore additional resources and examples available online.Remember,
awk
is a versatile tool, and its applications extend beyond Markdown manipulation. It can be used for various text processing tasks in different contexts.
Hi guys, I recently started working at a company with about 50 people that has grown to large for their current IT setup. They have no documentation or any SOPs. Has anyone been in a similar situation and how did you go about creating documentation, especially when you are new and don't fully understand all of the services they have in place?
Thankfully it's mostly a Microsoft shop and pretty low tech but there are dozens of exchange rules in place that no one knows why they exist or what they do, dozens of SharePoint sites with critical information strewn about them and so on. It's hard to think where to even start and decide what the best way to organize this information will be, and keep in a place a system where we will update it regularly. Any advice would be greatly appreciated.
I started a new job as a systems engineer not too long ago and am looking for a way to get comfortable with FOS as I've never had to manage FC switches before. Anyone know of a way to emulate it, or should I just resign myself to buying an old switch on ebay and throwing it in the rack?
Hi, all!
For those of you who work in organizations that do decent documentation, what are you using?
We currently just have a bunch of word docs in a SharePoint document library. I've previously used dedicated solutions for this such as Bookstack and Confluence. The company is very anti-Atlassian, so Confluence is out.
Just want to see what y'all are using as I search for a better solution.
Thanks!
https://twitter.com/RedSkyReady/status/1669781940411531264
cross-posted from: https://lemmy.world/post/158455
I sometimes have to use remote systems that I don't have root access to. I often find that I need to install packages in my home directory, so either I build from source or copy over my own pre-compiled versions.
Recently I've found out about pkgsrc. I'm looking for opinions from anyone who has used it to install packages without root access. Any feedback is useful!
cross-posted from: https://sh.itjust.works/post/87144
Received this QNAP security bulletin this morning. Update your QNAP products!
June 14, 2023 - QNAP® had published security enhancement against security vulnerabilities that could affect specific versions of QNAP products. Please use the following information and solutions to correct the security issues and vulnerabilities.
Vulnerabilities in Samba
Release date: June 14, 2023 Security ID: QSA-23-05 Severity: Medium CVE identifier: CVE-2022-37966 | CVE-2022-37967 | CVE-2022-38023 | CVE-2022-45141 Affected products: Certain QNAP Devices
Summary
The Samba Team has released security updates to address vulnerabilities in multiple versions of Samba, including vulnerabilities related to RC4 encryption. If exploited, some of these vulnerabilities allow an attacker to take control of an affected system. The following QNAP operating systems are affected:
• QTS, QuTS hero, QuTScloud, QVP (QVR Pro appliances) QES is not affected.
Only QNAP devices that run the affected operating systems and also act as a domain controller or AD member are affected.
Standalone QNAP devices are not affected by the vulnerabilities.
QNAP is currently fixing the vulnerabilities in QTS, QuTS hero, QuTScloud and QVP (QVR Pro appliances).
Please check this security advisory regularly for updates and promptly update your QNAP operating system to the latest version as soon as it is available.
Recommendation
Because RC4 encryption poses a high security risk, we strongly recommend replacing RC4 with the more secure AES algorithm when using a QNAP device as a domain controller or AD member.
• When the QNAP device acts as a domain controller, we strongly recommend enforcing AES encryption. • When the QNAP device acts as an AD member, the encryption method should follow that of the domain controller. We also strongly recommend that the domain controller is configured to enforce AES encryption. Before security updates are available, depending on the AD domain role of your QNAP device, we recommend enforcing AES encryption only or at least allowing both AES and RC4 encryption to mitigate the risks posed by the vulnerabilities.