Comment by chubot

I'm pretty sure that historically shell is the common influence of PHP, Perl, and Tcl.

PHP also inherits shell's here doc syntax, e.g. <<EOF . Not sure if Perl has that.

Actually PHP started out as a bunch of cgi-bin scripts, if I recall. It was very much "a shell for the web".

It kind of annoys me that they all require $ on the left, whereas shell only requires it on the right, which somehow makes more sense to me, e.g.

    a=$b  # shell

    $a = $b  # PHP and I think Perl