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Cheat sheets

• AWK cheat sheet
• curl cheat sheet
• dmidecode cheat sheet
• du cheat sheet
• find cheat sheet
• ip cheat sheet
• journalctl cheat sheet
• lsof cheat sheet
• ss cheat sheet
• strace cheat sheet
• systemctl cheat sheet
• systemd cheat sheet
• tar cheat sheet

Hardware

• Frequently Asked Questions
  • How to list all USB devices
  • How to see BIOS details
  • How to see hard disk specifications and details
  • How to see memory information such as type and speed
  • How to see the available hard disks

Kernel

• Frequently Asked Questions
  • How to find the specific cause of a tainted kernel
  • What is a tainted kernel
• Sysctl
  • kernel
    • kernel.tainted

Linux file systems

• Frequently Asked Questions
  • How to find the biggest directories on disk
  • How to securely delete a file and its contents
  • How to see the creation date of a file
• How to find hard links or files that point to a specific file
• Linux file permissions
  • How to change file permissions
  • Introduction in Linux file permissions
• Understanding the output of the stat command

Linux security frameworks

• AppArmor
• SELinux

Networking

• Frequently Asked Questions
  • How to see errors on dropped packets on a network interface on Linux
  • How to see open ports on Linux
  • How to see the default gateway on Linux
  • How to see the TTL value of a DNS record
  • How to see which process is using a port

Processes

• Kill a process that won't respond to CTRL+C

Shell scripting

• Making scripts (more) secure and safe
• Prompt for user input in a shell script
• Strip one or more characters from a variable or output

Software

• Package manager
  • Frequently Asked Questions
    • How to show all installed packages on Ubuntu
  • List installed packages on a Linux system

System administration

• Methods to find the Linux distribution and version

systemd

• Frequently Asked Questions
  • How to disable a systemd unit with systemctl
  • How to see the last X lines with journalctl
  • How to show failed units with systemctl
  • How to start and enable a unit with systemctl
• Systemd units and their purpose

Web

• Adding the Expires header to improving caching of static content in nginx
• How to log only some requests to a log file in nginx
• How to see all virtual hosts in nginx
• Nginx security hardening guide
• Pre-compress static assets with Brotli and Gzip
• Test web server caching with curl

Website information

• Latest changes
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