v=abcd
[ "${#v}" = 4 ] || echo '${#v} wrong'
v=$$
[ "${#$}" = "${#v}" ] || echo '${#$} wrong'
[ "${#!}" = 0 ] || echo '${#!} wrong'
set -- 01 2 3 4 5 6 7 8 9 10 11 12 0013
[ "${#1}" = 2 ] || echo '${#1} wrong'
[ "${#13}" = 4 ] || echo '${#13} wrong'
v=$0
[ "${#0}" = "${#v}" ] || echo '${#0} wrong'