🛠 Linux Command Reference for SREs

🚀 Categories and Commands#

🗂 File Management#

• Navigation and Basics:

  • ls - List directory contents.
  • cd - Change directory.
  • pwd - Display the current directory.

• File Operations:

  • cp - Copy files or directories.
  • mv - Move or rename files.
  • rm - Delete files or directories.
  • find - Search for files or directories.

• Disk Usage:

  • df - Show disk space usage.
  • du - Display directory or file sizes.

• Archiving:

  • tar - Archive and compress files.
  • zip/unzip - Compress and extract files in ZIP format.

🌐 Networking#

• Basic Commands:

  • ifconfig / ip - Display or manage network interfaces.
  • ping - Check connectivity to a host.
  • traceroute - Trace the path packets take to a host.

• Data Transfers:

  • curl - Transfer data from/to a URL.
  • wget - Download files from the web.

• DNS Tools:

  • dig - Query DNS servers.
  • nslookup - Query DNS records.

• Connections:

  • netstat / ss - Show active network connections.
  • lsof - List open files and their network connections.

🧠 Process Management#

• Monitoring:

  • ps - Display process information.
  • top / htop - Real-time process monitoring.

• Control:

  • kill - Terminate a process by PID.
  • killall - Terminate processes by name.
  • pkill - Kill processes by pattern.

• Prioritization:

  • nice - Start a process with a specific priority.
  • renice - Change priority of a running process.

• Background Jobs:

  • jobs - List background jobs.
  • fg - Bring a background job to the foreground.

📊 Performance Monitoring#

• System Metrics:

  • vmstat - Display system performance statistics.
  • uptime - Show system uptime.
  • free - Display memory usage.

• I/O Monitoring:

  • iotop - Monitor disk I/O.
  • iostat - Show CPU and I/O statistics.

• Advanced Tools:

  • sar - Collect and display system activity.
  • dstat - Show detailed system resource usage.

📜 Log Management#

• Viewing Logs:

  • cat / less / tail - View log files.
  • journalctl - View systemd logs.

• Searching and Filtering:

  • grep - Search text in files.
  • awk - Advanced text processing.
  • sed - Stream editing of text.

• Log Rotation:

  • logrotate - Manage log rotation and compression.

🛠 Disk and Filesystem#

• Disk Information:

  • lsblk - List information about block devices.
  • blkid - Display block device attributes.
  • df - Show filesystem disk space usage.

• Mounting:

  • mount - Mount a filesystem.
  • umount - Unmount a filesystem.

• Filesystem Checks:

  • fsck - Check and repair a filesystem.

• Partitioning:

  • fdisk - Manage disk partitions.

👥 User Management#

• User Information:

  • whoami - Display the current user.
  • id - Show user ID and group ID.
  • groups - Display groups a user belongs to.

• Account Management:

  • adduser - Add a new user.
  • passwd - Change a user’s password.

• Monitoring Users:

  • who - Show logged-in users.
  • w - Display active users and their processes.

• Privileges:

  • sudo - Run commands as another user.

🔒 Security and Permissions#

• File Permissions:

  • chmod - Change file permissions.
  • chown - Change file owner or group.

• Access Control:

  • umask - Set default permissions for new files.

🧰 Miscellaneous#

• Text Utilities:

  • echo - Print text to the console.
  • wc - Count lines, words, and characters in a file.

• System Information:

  • uname - Display system information.
  • uptime - Show system uptime.

• Scheduling:

  • cron - Schedule tasks.
  • at - Schedule tasks to run once.

❤️ Contributors#

• Curated by Ankush Patil.