wrestool: 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/wrestool - from package: icoutils

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

On Debian possible default full paths are:

/usr/bin/wrestool - from package: icoutils

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

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