f=0123456789; echo "f:1: =|${f:1:}|"
f=0123456789; echo "f:: =|${f::}|"
+echo "Substrings from special vars"
+echo '? '"=|$?|"
+echo '?:1 '"=|${?:1}|"
+echo '?:1:2'"=|${?:1:2}|"
+echo '?::2 '"=|${?::2}|"
+echo '?:1: '"=|${?:1:}|"
+echo '?:: '"=|${?::}|"
+set -- 1 2 3 4 5 6 7 8 9 10 11
+echo '# '"=|$#|"
+echo '#:1 '"=|${#:1}|"
+echo '#:1:2'"=|${#:1:2}|"
+echo '#::2 '"=|${#::2}|"
+echo '#:1: '"=|${#:1:}|"
+echo '#:: '"=|${#::}|"
+
echo "Substrings with expressions"
f=01234567; echo 'f '"=|$f|"
f=01234567; echo 'f:1+1:2+2 '"=|${f:1+1:2+2}|"