$ echo 'Fuck you!' > fuck_you.c; gcc fuck_you.c fuck_you.c:1:1: error: unknown type name ‘Fuck’ fuck_you.c:1:9: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘!’ token
$ echo 'Fuck you!' | gcc -xc
clang: error: no input files