cedric simon I think I may be misunderstanding the situation then. I was assuming you'd had something like this:

abbr -g php "/usr/local/php/5.4/bin/php"

Is that the sort of thing you mean? If so, given that, what was the problem you actually ran into? I have something similar to the above for a couple of abbreviations and I can't say I'm running into an issue.

Dave Pearson You are right, I have something similar. But I just solved my problem.

What I didn't know, was how to bypass the abbreviation. Let's say I have 2 php version: /usr/local/php/5.4/bin/php and /usr/local/php/7.3/bin/php. Also, php 7.3 is in my $path. I have an abbreviation as php for the version 5.4.

So fish will expand all my php commands with the full path to 5.4 I have set up. But I didn't find how to use the php command in my path because the abbreviation was expanded.
But I just discovered that it's the same as when we use a 'raw' command instead of its alias. Simply by adding a \ before, this will bypass aliases and abbreviations.

So I just can type \php and the php command in my path (the 7.3) will run ;)

cedric simon Ahh! Right, now I understand. Not a situation I've run into so good to know for future reference.