The usage of three basic linux commands and a little directory structure information will allow you to learn how to fully utilize any Linux command. These three commands are: cd, ls and man. Start off by using cd to change directories to one listed within the directory structure information section. Alternatively you could skip using cd completely.
Next we use ls to show us the commands that are located within that directory structure. If you choose to skip using cd then you can define the directory structure within the ls command, both variations are shown below.
#If you prefer to skip the cd step the use following command ls /bin Lastly we find the command we are interested in finding information and perform a man invocation on that command.
#if you prefer to skip the cd step use the following command man /bin/grep Directory Structure Information: /bin The /bin directory contains a small number of commands, some require root access and some do not and some commands . For the most part the majority of the basic commands are covered wtihin this directory. /sbin The /sbin directory contains commands that require root user permissions, also referred to as administrator or superuser permissions. Many of these commands are used in configuration of hardware in one way or another or during the boot process. /usr/bin The /usr/bin directory contains commands that have permissions allowing users to read or execute them. The vast majority of commands run by users are located within this directory. /usr/sbin The /usr/sbin directory contains commands that for the most part are able to be read and executed by users. However the majority of users should not require most of the programs within this structure.