[SOLVED] Difference between $PATH and ${PATH:+:${PATH}} in Linux environments

Issue

I see two different ways of adding path in Linux. For example,

export PATH=/usr/local/cuda/bin${PATH:+:${PATH}}
export PATH=/usr/local/cuda/bin:$PATH

While I am clearly aware of the second way, what is first way doing? What are the advantages over the second?

Solution

When PATH is empty, then:

export PATH=/usr/local/cuda/bin:$PATH

Results in

PATH=/usr/local/cuda/bin:

The empty :<nothing> is indicates current working directory, reference https://www.gnu.org/software/bash/manual/bash.html#index-PATH . The code added current working directory and cuda to path. This is not intended.

Instead, you want to add a : only if PATH is not empty. This is what ${PATH:+:${PATH}} achieves.

Answered By - KamilCuk

Answer Checked By - Gilberto Lyons (WPSolving Admin)