Essential Linux Commands for Developers

System Information

• uname -a: Displays all system information, including kernel version and hardware architecture.

• top: Provides a dynamic real-time view of running system processes.

• htop (needs installation on some distros): An interactive process viewer, similar to top but more user-friendly.

• df -h: Shows disk space usage on all mounted filesystems, in human-readable form.

• free -h: Displays the amount of free and used memory in the system, in human-readable form.

User Management

• useradd : Creates a new user account.

• usermod -aG : Adds a user to a specified group.

• passwd : Sets or changes the password for a user account.

• chage -l : Lists password aging information for a user.

File and Directory Management

• ls -lah: Lists all files and directories in the current directory, including hidden files, with detailed information in a human-readable format.

• find / -name : Searches the entire filesystem for a file or directory named .

• tar czvf archive.tar.gz /path/to/directory: Creates a compressed tar archive of a directory.

• chmod +x script.sh: Makes a script executable.

Package Management

• apt update && apt upgrade (Debian, Ubuntu, and derivatives): Updates the package index and upgrades all packages to their latest versions.

• yum update (CentOS, RHEL): Updates all installed packages to their latest version.

• dnf update (Fedora, newer RHEL): Similar to yum, but uses the DNF package manager.

Network Configuration and Troubleshooting

• ip addr show: Displays IP addresses and all network interfaces.

• netstat -tulnp: Lists all active listening ports along with the corresponding service.

• ping google.com: Sends ICMP ECHO_REQUEST packets to google.com to test connectivity.

• traceroute google.com: Traces the route packets take from your machine to google.com

Process Management

• ps aux: Shows running processes with detailed information.

• kill : Sends a SIGTERM to a process with the specified PID, requesting its termination.

• killall : Terminates all processes with the given name.

• systemctl restart : Restarts a systemd service.

System Monitoring and Performance

• vmstat: Reports virtual memory statistics.

• iostat: Provides CPU and input/output statistics for devices and partitions.

• lsof: Lists open files and the processes that opened them.

Disk Usage and Files

• du -sh /path/to/directory: Shows the total size of a directory and its subdirectories in a human-readable format.

• ncdu (needs installation on some distros): An interactive disk usage viewer, providing a detailed breakdown of which files and directories are using disk space.