Bash maintains an internal hash of previously found executables in your path. In this case, it has details that at one time there was an executable at /usr/bin/siege, and reuses that path to avoid having to search again. You need to tell bash to manually rehash the path for siege like so: hash siege You can also clear all hashed locations: hash -r

Remember there are two kinds of variable. Internal Variables and Environment Variables. PATH should be an environment variable.

All shells should tell you that your path is the same thing with BOTH of the two commands: # The PATH variable echo "$PATH" # The PATH environment variable env | /bin/grep PATH

I think it's very confusing to overload common executables, such as yarn, in the /bin directory as I often put that bin directory first in my path. Thus, I'd unexpectedly get the bin/yarn rather than my system yarn, which I manage with yvm.

However, the place where pip places that package might not be in your $PATH (thus requiring you to manually update your $PATH afterwards), and on windows the pip install might not take care of python-specific issues for you (see "Notes for Windows Users", above). As such, installation via package managers is recommended instead.

the bullet-proof way to add a path (e.g., ~/opt/bin) to the PATH environment variable is PATH="${PATH:+${PATH}:}~/opt/bin"