rpmquery: 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/rpmquery - from package: rpm

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

On Debian possible default full paths are:

/usr/bin/rpmquery - from package: rpm

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

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