The -d option selects a detail level; the normal level is 0, a detail level of 1 prints a bit more information, and a detail level of 2 prints more information than is useful (probably!).
The options -h, -p, -f, -s, and -o indicate whether information should be printed about the header, pages, fonts, specials, and opcodes in the DVI files. The -a option turns on all of these options.
If no input file is specified on the command line, the input is read from the standard input.
dvishow -d 2 -a input.dvi