You must use the "source" command to establish the environment.  The following is from the release notes

Establishing the Compiler Environment

The ifortvars.sh (ifortvars.csh) script, used to set up the command-line build
environment, has changed. In previous versions, you chose the target platform by selecting
either the fc or fce directory root. In version 11.x, there is one version of these scripts and
they now take an argument to select the target platform.

The command takes the form:

source <install-dir>/Compiler/11.1/xxx/bin/ifortvars.sh argument

Where <install-dir> is the installation directory (default for system-wide installation is
/opt/intel) and xxx is the update number and argument is one of ia32, intel64, ia64
as described above under Installation Folders. Establishing the compiler environment also
establishes the Intel® Debugger (idb) environment.


Uninstall instructions are also in the release notes.