Terminal Command Line Bash – Why Does `echo $path` Show a Blank Line

unset it

unset DYLD_LIBRARY_PATH

The bash reference manual says

Once a variable is set, it may be unset only by using the unset builtin command.

If the path includes spaces, you're going to need to quote it.

Your line export PATH=/Users/ps1/Documents/PS 1/whatever-else/:$PATH causes Bash to interpret the PATH=/Users/ps1/Documents/PS part as the full first argument to your PATH—telling export to set the PATH to only the section before the space. If you use export "PATH=/Users/ps1/Documents/PS 1/whatever-else/:$PATH", it will interpret the entire PATH=/Users/ps1/Documents/PS 1/whatever-else/:$PATH as part of the first argument. By convention, most people only quote the right side of the equals sign, because it looks nicer, it's the only thing that needs quoted, and bash automatically concatenates strings with no spaces between them.