whatis:tldr:c0ae8

The command "whatis" is used in Linux and Unix systems to provide brief descriptions or summaries of a given keyword or command. The ${keyword1} and ${keyword2} in the command represent the keywords or commands that you want to look up.

For example, if you execute the command "whatis ls", it will display a short description of the "ls" command, which is used to list the files and directories in a Linux/Unix system.

In the case of "whatis ${keyword1} ${keyword2}", you can replace ${keyword1} and ${keyword2} with any keywords or commands you want to learn about. For instance, "whatis cat grep" will display a brief explanation for both the "cat" and "grep" commands, if they exist in the system documentation.

Note that the output of the "whatis" command depends on the available system documentation, so not all keywords or commands may have descriptions associated with them.