pkgdb-cli: 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/pkgdb-cli - from package: packagedb-cli

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

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