ovirt-shell: command not found

Have You tried accessing the binary with the full path?

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/ovirt-shell - from package: ovirt-engine-cli

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