Wow! That's really impressing, what you do with your shell. Suppose I have to read perlrun to learn all this stuff!
Finally I understood, for what I have to search: \x{1f618} !!! But why my replacement is not working?
I am stumbled! marek

while(<>) {
# foreach (/\x{1f618}/g) {print "hurray! And here is your emoticon!\n"
+}; # this is working!!!
# foreach (/\x{1f695}/g) {print "hurray! And here is your emoticon!\n"
+}; # this is working!!! This is for the taxi
    s/\x{1f618}/latex_code/g;
}
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