AT&T syntax
The x86 assembly spelling GCC, Clang and objdump print by default - source first, % before registers, $ before numbers.
AT&T syntax writes x86 instructions as mnemonic source, destination with %register, $immediate, size suffixes and disp(base,index,scale) memory operands.
Examples
Intel's
mov rax, 5is AT&T'smovq $5, %rax: source first,$on constants,%on registers.