setting up path programs and other executable files can be in many directoriesso operating systems provide search path thatlists the directories that the os searches for executables the path is stored in an environment variablewhich is named string maintained by the operating system this variable contains information available to the command shell and other programs the path variable is named as path in unix or path in windows (unix is case sensitivewindows is notin mac osthe installer handles the path details to invoke the python interpreter from any particular directoryyou must add the python directory to your path setting path at unix/linux to add the python directory to the path for particular session in unixrefer the followingin the csh shelltype setenv path "$path:/usr/local/bin/pythonand press enter in the bash shell (linux)type export ath="$path:/usr/local/bin/pythonand press enter in the sh or ksh shelltype path="$path:/usr/local/bin/pythonand press enter note/usr/local/bin/python is the path of the python directory setting path at windows to add the python directory to the path for particular session in windowsrefer the followingat the command prompttype path %path%; :\python and press enter notec:\python is the path of the python directory python environment variables here in the table beloware important environment variableswhich can be recognised by python sr no variable description pythonpath it has role similar to path this variable tells the python interpreterwhere to locate the module files imported into program it should include the python source library directory and the directories containing python source code pythonpath is sometimespreset by the python installer