How to fix ln: failed to create symbolic link error?

Question

PhantomJS

I install casperjs according to the manual via git docs.casperjs.org/en/latest/installation.html#inst...
but after the command ln -sf `pwd`/bin/casperjs /usr/local/bin/casperjs
an error appears ln: failed to create symbolic link '/usr/local/bin/casperjs': No such file or
directory