For binaries to be accessible from the command line, their locations must be part of the
PATH environment variable. If you do the following
(filling in the correct path), you will be able to call
pdflatex directly (as well as every other program in the same directory. To make the change permanent,
export the command in a file sourced by the shell, such as
.profile (assuming you use bash).
Either use an editor or run
echo "export PATH=$PATH:/usr/local/texlive/2014/.../bin" >> ~/.bash_login
Which will append the output of the
echo command to the file and create it if it does not exist.
The shell searches the directories in the
PATH in the order they are listed, so usually it is a good idea to always append to the
PATH unless you know exactly what is in the added directory. It might contain other executables with the same name as other programs which are already in the
PATH. Having these shadowed can sometimes lead to surprises.