isutf8: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/isutf8 - from package: moreutils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/isutf8 - from package: moreutils

You may install the required package with command apt-get install {package}

Error in other languages:
isutf8: bevel nie gevind nie
isutf8: comandă negăsită
isutf8: comando não encontrado
isutf8: commande introuvable
isutf8: command not found
isutf8: käsku ei ole
isutf8: không tìm thấy lệnh
isutf8: komanda nerasta
isutf8: Kommando nicht gefunden.
isutf8: kommandot finns inte
isutf8: komut yok
isutf8: nie znaleziono polecenia
isutf8: níor aimsíodh an t-ordú
isutf8: no se encontró la orden
isutf8: no s'ha trobat l'ordre
isutf8: opdracht niet gevonden
isutf8: parancs nem található
isutf8: perintah tidak ditemukan
isutf8: príkaz nenájdený
isutf8: příkaz nenalezen
isutf8: команда не найдена
isutf8: командата не е открита
isutf8: 命令找不到
isutf8: コマンドが見つかりません