MacOS – What does adding PATH to .bashrc do

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.

When you did:

export PATH="~/.composer/vendor/bin/laravel"

You changed the system default PATH to something nearly useless. You should never replace PATH, you should only append to PATH.

Remove the following two lines from your ~/.bash_profile:

export PATH=/Applications/MAMP/bin/php/php5.5.10/bin:$PATH
export PATH="~/.composer/vendor/bin/laravel"

And replace them with the following:

pathadd() {
    if [ -d "$1" ] && [[ ":$PATH:" != *":$1:"* ]]; then
        PATH="${PATH:+"$PATH:"}$1"
    fi
}
pathadd /Applications/MAMP/bin/php/php5.5.10/bin
pathadd ~/.composer/vendor/bin/laravel
export PATH

This is a safe way to append to your PATH environment variable. It only does the append if the path isn't already in the list.