Reverse string in bash missing

Question

All,

I have a decrypt process which has a part that reverses an encoded (only as another ascii character) string.

The string is...

vtr«¥ºc€a

And the reverse command I'm using is...

enc_pass="vtr«­¥ºc€a"
reverse=""

len=${#enc_pass}
for (( i=$len-1; i>=0; i-- ))
do
      reverse="$reverse${enc_pass:$i:1}"
done

echo $reverse

But when I check the length, it comes out as 9 characters long rather than 10, and I've found out its the € character which is being ignored.

Is there any way to cater for this? I'm pretty lost on it, not sure where to go next.

---

It turns out the main issue was with my LANG on the new server. The old server had LANG="en_GB" and the new server LANG="en_GB.UTF-8"

Changing the LANG back to en_GB resolved the reversing as UTF-8 ignored the character for some reason.

Answer 1

You can use rev utility:

enc_pass="vtr«­¥ºc€a"
rev <<< "$enc_pass"
a€cº¥­«rtv

Answer 2

LC_ALL='en_US.UTF-8'
(your code)
echo "${#reverse}"
10

LC_ALL='C'
(your code)
echo "${#reverse}"
16

I think you must just have a localization/encoding problem in your environment. I suspect that would even effect rev , although it's a nonstandard utility so I can't say for sure. This works fine for me:

rev() {
    local -x LC_ALL=en_US.UTF-8
    if [[ ! "$1" ]]; then
        echo
        return
    fi
    printf '%s' "${1: -1:1}"
    rev "${1:0: -1}"
}
$ rev 'vtr«­¥ºc€a'
a€cº¥­«rtv

Answer 3

rev command is of no great help, at least for binary files because rev terminates at 0x00.

$ export LC_ALL='en_US.UTF-8'
$ echo -e "\xe4" | rev
rev: stdin: Invalid or incomplete multibyte or wide character
$ 
$ export LC_ALL='de_DE.ISO-8859-1'
$ echo -e "\xe4" | rev | od -tx1
0000000 e4 0a
0000002
$ 
$ export LC_ALL='en_US.UTF-8'
$ echo -e "te\x00st" | rev | od -tx1
0000000 65 74 0a
0000003
$