With this command you can check

With this command you can check, which command would be executed. An example: If you save this tools in a directory c: ools and you have added this directory to your PATH variable, than an input like which which produce the output "WHICH.EXE" in "C:TOOLS" will be executed wheras which dir will give you "DIR" is an internal MS-DOS command and will be executed. First of all, which checks if it is an internal MS-DOS COMMAND. After that it searches through all directories you have mentioned in your PATH variable (just like the MS-DOS commandline behaves).