#!/bin/bash
s="%H1256
*+E1111
*;E2311
+-'E3211
{E4511
DE4513"
sed -n 's/.*\([[:upper:]][[:digit:]]*\).*/\1/p' <<< "$s"
echo "---"
grep -oE '[[:upper:]][[:digit:]]+' <<< "$s"
IyEvYmluL2Jhc2gKcz0iJUgxMjU2CiorRTExMTEKICAqO0UyMzExCiAgICstJ0UzMjExCiAgICAgIHtFNDUxMQogICAgICAgREU0NTEzIgoKc2VkIC1uICdzLy4qXChbWzp1cHBlcjpdXVtbOmRpZ2l0Ol1dKlwpLiovXDEvcCcgPDw8ICIkcyIKZWNobyAiLS0tIgpncmVwIC1vRSAnW1s6dXBwZXI6XV1bWzpkaWdpdDpdXSsnIDw8PCAiJHMi