Final answer:
In Ubuntu Linux, the 'sudo' command is used to gain permission to install software.
Step-by-step explanation:
In Ubuntu Linux, the command 'sudo' is used to gain permission to install software. Sudo stands for 'superuser do' and allows the user to execute a command with administrative privileges.
To use the sudo command, you would type 'sudo' followed by the command you want to execute. For example, to install software, you would use 'sudo apt-get install [package_name]'.
Using the sudo command grants temporary access to system files and settings, ensuring that only authorized users can make changes to the system.