Some commands require a parameter, such as the name of a file. If a file name without a path is specified on a command, the file is assumed to be in the current directory. You always can specify the complete path for the file. When a file name is used on command, you usually can use wild cards to specify a group of commands. These commands manipulate directories and require the name of a directory as a parameter.
File permissions give other users the ability read , write , or execute a file.
Permissions can be granted to another user in your group, or all others.