cat - Lets you view the contents of a file. Many linux commands can use the redirection symbol > to redirect the output of the command. For example, use the redirection symbol with the cat command to copy a file: cat /etc/shells > newfile ( the contents of the shells file are written to newfile ). cd - Changes the directory. chmod - This command changes the attributes assigned to a file. clear - Clears the screen. This command is useful when the screen has become cluttered with commands and data that you no longer need to view. cp - Used to copy a file. date - Entered alone, this command displays the current system date settings. Entered in the format date , this command sete the system date. echo - Displays information on the screen. fdisk - Creates or makes changes to a hard drive partition table. grep - Searches for a specific pattern in a file or in multiple files. hostname - Displays a server's FQDN. ifconfig - Used to troubleshoot problems with network connec...