the location of these programs is in your path variable

When asked to execute a program, the shell needs to know where the program is

you can do this in 3 ways

Give the absolute path to the binary
/bin/ls
/usr/bin/firefox
/home/user/program

Give a relative path (relative to the current directory)
./program - run "program" located in the current directory

Most "installed" programs, however, are located in special locations
When asked to execute a program with no location information, the shell will look through these special locations in order to find the program

These special locations are stored in the PATH variable

do
Code:
echo $PATH
If you want to be able to execute locally build programs without specifying their location, you need to add an additional directory to the path

Code:
mkdir ~/bin
compile all your programs into ~/bin, and you can just type the program name