Tuesday, October 3, 2023

SSH Key Management and Troubleshooting on RHEL

SSH Key Management and Troubleshooting on RHEL

Introduction

This tutorial aims to provide a comprehensive guide on managing SSH keys, setting the correct permissions, and troubleshooting common issues on a Red Hat Enterprise Linux (RHEL) system.

SSH Key Components

id_rsa and id_rsa.pub

  • id_rsa: This is your private key. Keep it secure and never share it.
  • id_rsa.pub: This is your public key. You can safely share it with others.

Setting Permissions

.ssh Directory

  • Directory Permissions: 700
  • Owner: The user who owns the home directory
  • Group: Usually the primary group of the user

Commands:

chown username:username ~/.ssh
chmod 700 ~/.ssh

authorized_keys File

  • File Permissions: 600

Commands:

chown username:username ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys

id_rsa and id_rsa.pub Files

  • id_rsa File Permissions: 600
  • id_rsa.pub File Permissions: 644

Commands:

chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub

Generating SSH Keys

To generate SSH keys, you can use the ssh-keygen command:

ssh-keygen -t rsa -b 4096

Copying Keys to a Remote Server

You can use the ssh-copy-id command to copy your public key to a remote server:

ssh-copy-id username@remote-server

Troubleshooting

SELinux

If you encounter issues, SELinux could be a factor. On RHEL, you may need to set it to Permissive mode.

Commands:

setenforce 0
sestatus

Note: This is not recommended for production systems.

Conclusion

This tutorial should provide you with the knowledge to manage SSH keys effectively on a RHEL system.

Top 15 Linux Commads

Top 15 Linux commands

Introduction:

Linux is a popular operating system used in various industries, including web development, data analysis, and scientific research. One of the reasons why Linux is so widely used is because of the powerful command-line interface it offers. Linux commands are used to interact with the system and perform various tasks, such as file management, network management, and process management. In this blog post, we will discuss the top 15 Linux commands that every user should know.

  1. ls:

The "ls" command is used to list the contents of a directory. It is one of the most commonly used commands in Linux. By default, it shows the contents of the current directory. You can also specify a directory path as an argument to list the contents of a specific directory.

  1. cd:

The "cd" command is used to change the current working directory. It is used to navigate through the file system. For example, if you want to change the working directory to the "Documents" directory, you can use the command "cd Documents".

  1. pwd:

The "pwd" command is used to display the current working directory. It shows the full path of the current directory. This command is helpful when you want to know the current directory path.

  1. mkdir:

The "mkdir" command is used to create a new directory. It takes a directory name as an argument and creates a new directory with that name. For example, "mkdir new_directory" will create a new directory named "new_directory" in the current working directory.

  1. rmdir:

The "rmdir" command is used to remove an empty directory. It takes a directory name as an argument and removes the directory with that name. For example, "rmdir empty_directory" will remove the "empty_directory" directory if it is empty.

  1. rm:

The "rm" command is used to remove files or directories. It takes a file or directory name as an argument and removes it. You can use the "-r" option to remove a directory and its contents recursively. For example, "rm -r directory" will remove the "directory" directory and all its contents.

  1. cp:

The "cp" command is used to copy files or directories. It takes two arguments: the source file/directory and the destination file/directory. You can use the "-r" option to copy a directory and its contents recursively. For example, "cp file.txt /path/to/destination" will copy the "file.txt" file to the "/path/to/destination" directory.

  1. mv:

The "mv" command is used to move or rename files or directories. It takes two arguments: the source file/directory and the destination file/directory. If the destination is a directory, it moves the source file/directory to that directory. If the destination is a file, it renames the source file/directory to the destination file name. For example, "mv file.txt new_file.txt" will rename the "file.txt" file to "new_file.txt".

  1. cat:

The "cat" command is used to concatenate and display the contents of files. It takes one or more file names as arguments and displays their contents. For example, "cat file1.txt file2.txt" will display the contents of "file1.txt" and "file2.txt".

  1. grep:

The "grep" command is used to search for a pattern in files. It takes a pattern and one or more file names as arguments and displays the lines that contain the pattern. For example, "grep 'pattern' file.txt" will display the lines that contain the "pattern" in the "file.txt"

Chicken Alfredo

Chicken Alfredo Recipe

Chicken Alfredo with Bow Tie Noodles

Ingredients:

  • 2 chicken breasts
  • 8 oz bow tie noodles (also called farfalle)
  • Salt and pepper to taste
  • 2 tbsp olive oil

Ingredients for Alfredo Sauce:

  • 1 cup heavy cream
  • 1/2 cup unsalted butter
  • 1 cup grated Parmesan cheese
  • Salt and pepper to taste

Instructions:

Prepare Chicken

  1. Season the chicken breasts with salt and pepper.
  2. Heat 2 tablespoons of olive oil in a skillet over medium heat.
  3. Cook the chicken breasts until they're cooked through, about 7-8 minutes per side, depending on thickness.
  4. Remove chicken from skillet and let it rest for a few minutes before slicing into strips.

Prepare Pasta

  1. Bring a large pot of salted water to a boil.
  2. Cook the bow tie noodles according to package directions until al dente.
  3. Drain the pasta and set aside.

Prepare Alfredo Sauce

  1. In a saucepan, melt the butter over medium-low heat.
  2. Add the heavy cream and stir to combine.
  3. Heat the mixture until it's warm but not boiling.
  4. Gradually add the grated Parmesan cheese, stirring constantly until fully incorporated.
  5. Season with salt and pepper.
  6. Stir continuously until the sauce thickens.
  7. Remove from heat.

Combine

  1. Add the cooked bow tie noodles and sliced chicken to the pan with the Alfredo sauce.
  2. Toss everything to combine, making sure the pasta and chicken are well-coated with the sauce.

Serve immediately, optionally garnishing with additional Parmesan or some chopped parsley. Enjoy your Chicken Alfredo!

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