为什么使用完整路径访问命令与仅通过命令名称不同？

Question

I added node to my path. My understanding is that I'm calling the same command using the following:

$ node --version
v10.24.1

$ which node
/usr/local/bin/node

$ /usr/local/bin/node --version
v14.17.0

My question is why the versions are different?

Answer 1

which will check the PATH , but in Bash it is not aware of builtins, aliases, or functions. Instead, it is safer to use type instead , which avoids these pitfalls.

In your example, the most likely explanation is that node is either an alias or a function. type node should give you a clue what gets executed, but apparently it is not the same binary as /usr/local/bin/node .

As an alternative, you can enable logging:

$ set -x
$ node

If it is an alias or function, you should see it in the output.

---

Here is a contrived example to demonstrate the difference between type and which (executed on Arch Linux):

$ node --version
v16.2.0

$ node () { 
  echo "v99.9.9"
}

$ node --version
v99.9.9

$ which node
/usr/bin/node

$ /usr/bin/node --version
v16.2.0

$ type node
node is a function
node () 
{ 
    echo "v99.9.9"
}