<P> where doSomething is, in effect, a verb, how an adverb (for example, should the command be executed "verbosely" or "quietly") and toFiles an object or objects (typically one or more files) on which the command should act . The> in the third example is a redirection operator, telling the command - line interpreter to send the output of the command not to its own standard output (the screen) but to the named file . This will overwrite the file . Using>> will redirect the output and append it to the file . Another redirection operator is the vertical bar (), which creates a pipeline where the output of one command becomes the input to the next command . </P> <P> One can modify the set of available commands by modifying which paths appear in the PATH environment variable . Under Unix, commands also need be marked as executable files . The directories in the path variable are searched in the order they are given . By re-ordering the path, one can run e.g. \ OS2 \ MDOS \ E. EXE instead of \ OS2 \ E. EXE, when the default is the opposite . Renaming of the executables also works: people often rename their favourite editor to EDIT, for example . </P> <P> The command line allows one to restrict available commands, such as access to advanced internal commands . The Windows CMD. EXE does this . Often, shareware programs will limit the range of commands, including printing a command' your administrator has disabled running batch files' from the prompt . </P> <P> Some CLIs, such as those in network routers, have a hierarchy of modes, with a different set of commands supported in each mode . The set of commands are grouped by association with security, system, interface, etc . In these systems the user might traverse through a series of sub-modes . For example, if the CLI had two modes called interface and system, the user might use the command interface to enter the interface mode . At this point, commands from the system mode may not be accessible and the user exits the interface mode and enters the system mode . </P>

What is written at the command line prompt to start the name server