nss_updatedb: 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 Debian possible default full paths are:

/usr/sbin/nss_updatedb - from package: nss-updatedb

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

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