reverse the order of characters in a string

Question

In string \"12345\", out string \"54321\". Preferably without third party tools and regex.

Answer 1

Some simple methods of reversing a string

echo '!!!esreveR si sihT' | grep -o . | tac | tr -d '\n' ; echo

echo '!!!esreveR si sihT' | fold -w 1 | tac | tr -d '\n' ; echo

Convert to hex values then reverse

echo '!!!esreveR si sihT' | xxd -p | grep -o .. | tac | xxd -r -p ; echo

echo '!!!esreveR si sihT' | xxd -p | fold -w 2 | tac | xxd -r -p ; echo