db2index: 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/db2index - from package: 389-ds-base

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

Error in other languages:
db2index: bevel nie gevind nie
db2index: comandă negăsită
db2index: comando não encontrado
db2index: commande introuvable
db2index: command not found
db2index: käsku ei ole
db2index: không tìm thấy lệnh
db2index: komanda nerasta
db2index: Kommando nicht gefunden.
db2index: kommandot finns inte
db2index: komut yok
db2index: nie znaleziono polecenia
db2index: níor aimsíodh an t-ordú
db2index: no se encontró la orden
db2index: no s'ha trobat l'ordre
db2index: opdracht niet gevonden
db2index: parancs nem található
db2index: perintah tidak ditemukan
db2index: príkaz nenájdený
db2index: příkaz nenalezen
db2index: команда не найдена
db2index: командата не е открита
db2index: 命令找不到
db2index: コマンドが見つかりません