14 Environment Variables

Purpose

Environment variables store configuration values that control how processes run. In CTFs, they can reveal hidden paths or misconfigurations. In real-world scenarios, sysadmins and penetration testers check variables like $PATH to debug issues or configure tools.

Core Commands

$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
#Prints The Current PATH Variable

$ export TEST=hello
#Creates a Temporary Environment Variable "TEST" with Value "hello"

$ echo $TEST
hello
#Prints Value of TEST Variable

$ nano ~/.bashrc
#Opens Bash Configuration File Where You Can Add Permanent Variables

Environment Variables Basics

• $PATH defines where the system looks for executables.
• export sets variables for the current session.
• Adding variables to ~/.bashrc makes them permanent across sessions.
• Misconfigured environment variables can break tools or create exploits.

Environment Variables Commands