File Permissions in Unix/Linux

File Permissions Unix & Linux provides Read(r),Write(w) and Execute(x) permissions to any file on the system. If you ls -l every file with its permissions will be shown. The system is divided into three types - User,Group and others. The r,w,x permissions are assigned to each type. This is well explained by the diagram shown below: Owner permissions − The owner’s permissions determine what actions the owner of the file can perform on the file.

PATH Environment Variable in Linux/Unix

What is the $PATH environment variable? Every Linux & Unix System has several environment variables which are dynamic variables essential for running several processes in the system. $HOME,$env being some of the well known environment variables. The $PATH environment variable stores all the paths where one can find the binary executables for all the commands that we use. Whenever a command is invoked from the terminal,all the paths in the $PATH environment variable are looked up and if the binary is found, the command is executed.