Month: October 2026
How to Use the apt Command in Linux
Use apt to find, install, update, and remove packages on Debian or Ubuntu. Compare upgrade modes, preview removals, verify results, and diagnose errors.
How to Install DEB Packages in Ubuntu
Install a downloaded DEB in Ubuntu with APT or a GUI. Check architecture and dependencies, interpret installation errors, and verify updates and package status.
How to Manage APT Repositories on Ubuntu
Find Ubuntu's APT source files, choose a supported PPA or vendor archive, configure signing keys, inspect package candidates, and troubleshoot errors.
How to Check the Ubuntu or Debian Version
Check your Ubuntu or Debian release with /etc/os-release, interpret version and codename fields, and resolve point-release or Testing/Sid mismatches.
How to SSH Into a Linux Server
Connect to a Linux server from Windows, macOS, or Linux. Use the right SSH command, verify the host key, and diagnose common login errors.
SSH Config File Examples: Set Up and Verify Host Profiles
Create SSH host aliases, select the intended key, understand config precedence, and inspect effective settings with ssh -G before debugging a connection.
How to Use ssh-copy-id and Verify SSH Key Login
Install the right SSH public key with ssh-copy-id, choose the correct user and port, verify which key authenticates, and recover from failed installation.
How to Fix SSH Permission Denied (publickey)
Fix SSH Permission denied (publickey) by reading debug output, checking client keys and server authorization, and finding a safe recovery route when locked out.
SCP Command in Linux: Copy Files, Directories, and Troubleshoot Errors
Use SCP to upload, download, and copy directories over SSH. Learn ports, keys, remote paths, checksum checks, permission fixes, and when to use rsync.
How to Use SFTP on Linux: Commands, SSH Keys, and Transfer Fixes
Connect with Linux SFTP, upload and download files, choose the correct SSH key, and distinguish connection, permissions, and batch-transfer failures.