Which command is used to list files in a directory?

The command used to list files in a directory is 'ls'. This command is a fundamental aspect of Unix and Linux operating systems, providing a simple yet effective means to view the contents of a directory. By default, 'ls' will display the names of the files and subdirectories in the current working directory, and it has various options to modify the output, such as showing hidden files or providing detailed information about file attributes.

While 'dir' is also a command used to list files, it is more commonly associated with DOS and Windows environments. In Unix/Linux, 'ls' is the more standard command, which makes it essential for those working within these systems. The other choices, 'list' and 'show', do not correspond to any standard command for listing directory contents in Linux or Unix environments. Knowing the 'ls' command and its options is crucial for basic file management in Linux.