Linux Command Reference – Quick & Clear

 

1. File and Directory Management

  • ls – List directory contents

  • cd – Change directory

  • pwd – Print working directory

  • cp – Copy files and directories

  • mv – Move or rename files

  • rm – Remove files or directories

  • mkdir – Create directories

  • rmdir – Remove empty directories

  • touch – Create files or update timestamps

  • tree – Display directory tree

  • stat – Display file or filesystem info

2. File Searching

  • find – Search files in a directory hierarchy

  • locate – Find files by name

3. Viewing and Editing Files

  • cat, tac – Display file content (normal/reverse)

  • more, less – Paginated or scrollable view

  • head, tail – Show beginning/end of a file

  • nano, vim, vi, emacs – Terminal text editors

  • grep, sed, awk – Search and manipulate text

  • cut, sort, uniq, tr, tee, paste, wc – Text processing utilities

4. Process Management

  • ps, top, htop – View running processes

  • kill, killall – Terminate processes

  • bg, fg, jobs – Manage jobs in shell

  • nice, renice – Set process priority

  • time, uptime – Execution time and system uptime

5. Networking

  • ip, ifconfig – Network interface configuration

  • ping, traceroute – Network diagnostics

  • netstat, ss – Connection stats

  • nslookup, dig – DNS tools

  • ssh, scp, ftp, curl, wget, telnet, nc – File transfer & remote access

  • nmap – Network scanning

  • iptables, firewalld, ufw – Firewall management

  • tcpdump – Network traffic capture

6. User and Group Management

  • useradd, usermod, userdel – Manage user accounts

  • groupadd, groupdel – Manage groups

  • passwd, chage – Password management

  • who, whoami, id, groups, w – User and session info

7. Package Management

  • apt, apt-get, dpkg – Debian/Ubuntu-based systems

  • yum, dnf, rpm – Red Hat/Fedora/CentOS-based systems

8. System Services

  • systemctl, service – Manage services (start/stop/status)

  • init – Runlevel management (legacy)

9. Scheduled Tasks

  • cron, crontab – Scheduled jobs

  • at, batch – One-time or load-based jobs

  • sleep – Delay command execution

10. Permissions and Security

  • chmod, chown, chgrp, umask – File permissions

  • setfacl, getfacl – Access control lists

  • sudo, visudo, sudoers, gpasswd – Elevated privileges

11. Backup and Restore

  • rsync, dd, cpio – Backup and restore tools

12. Containers and Orchestration

  • docker, docker-compose – Container management

  • kubectl – Kubernetes CLI

  • helm – Kubernetes package management

13. Automation & Configuration

  • ansible – Configuration automation

  • terraform – Infrastructure as Code (IaC)

  • puppet – Configuration state management

14. CI/CD Tools

  • Jenkins, GitLab CI, GitHub Actions – Continuous integration pipelines

15. Cloud Command-Line Tools

  • aws, az, gcloud – AWS, Azure, and Google Cloud CLI tools

16. Logging and Monitoring

  • Prometheus, Grafana – Metrics and dashboards

  • Elasticsearch, Logstash, Kibana (ELK) – Centralized logging and visualization