No, it's part of the shell. Do "man bash" or "man sh", then search with "/\!". From man bash: "If the reserved word ! precedes a pipeline, the exit status o

No, it's part of the shell. Do "man bash" or "man sh", then search with "/\!". From man bash: "If the reserved word ! precedes a pipeline, the exit status of that pipeline is the logical negation of the exit status".