reverse the order of characters in a string

Question

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

Answer 1

A bash solution improving over @osdyng answer (my edit was not accepted):

var="12345"     rev=""

for(( i=0 ; i<${#var} ; i++ )); do rev="${var:i:1}$rev"; done

echo "var: $var, rev: $rev"

Or an even simpler (bash) loop:

var=$1   len="${#var}"   i=0   rev=""

while (( i

A POSIX solution:

var="12345"     rev=""    i=1

while  [ "$i" -le "${#var}" ]
do     rev="$(echo "$var" | awk -v i="$i" '{print(substr($0,i,1))}')$rev"
       : $(( i+=1 ))
done

echo "var: $var, rev: $rev"

Note: This works on multi byte strings. Cut solutions will work only in ASCII (1 byte) strings.