My point is that mv is a compiled C program, not a shell builtin or piece of shell syntax, that you may nonetheless call in a shell script to extend the functionality of the shell. rename is another such compiled C program. To say that it's awkward to batch rename files with mv may be true, but that's a deficiency of an external C program being used beyond its original purpose. Since we're using external programs anyway, you can just use one that's actually designed explicitly for the purpose renaming files.