opensc-tool: 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/opensc-tool - from package: opensc

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

On Debian possible default full paths are:

/usr/bin/opensc-tool - from package: opensc

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

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