I was talking about bash scripts. But outperforming C with Julia is perfectly possible. Julia JIT compilation means you can remove overhead of a lot of function calls which C cannot do. A simple example would be sort taking a function pointer doing object comparison.

High level functional style code with things like map and filter can frequently be JIT compiled to optimal machine code.

Fortran is considered faster for numerical code than C and well polished Fortran libraries like BLAS is already getting outperformed by Julia.

For typical systems programming with need to tight control of memory and real time system C will still have the edge. But for anything crunching lots of numbers like data analysis or machine learning Julia will likely outperform everybody else.