netkey-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/netkey-tool - from package: opensc

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

On Debian possible default full paths are:

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

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

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