How can you set or change the value of an environment variable in the Linux operating system?

Variables in Linux can be set or modified using several methods:

• In the current terminal session:

export VARIABLE_NAME=value

For example:

export PATH=$PATH:/new/path

• To make a variable available in all new sessions, add it to the shell configuration file, such as ~/.bashrc, ~/.bash_profile, or /etc/environment (for system variables).

Example of adding to ~/.bashrc:

export MY_VAR="my_value"

After editing the file, run source ~/.bashrc or restart the terminal to apply changes.

Thus, temporarily — via export in the terminal, permanently — through shell configuration files.