"That was actually unneeded. (No big deal ... just FYI.) ..."

Well, that surprised me but it seems you are quite correct:

$ perl -e "print 'qwe'"
qwe

$ perl -e "my $x = 'qwe'; print $x"
syntax error at -e line 1, near "my  ="
Execution of -e aborted due to compilation errors.
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I've had so much trouble with perl -e "..." in the past, that I now just automatically write perl -e '...', without giving it a second thought. I suppose my one-liners usually have a variable. Anyway, good to know; although, my muscle memory may take some convincing. :-)