snmp-ups: 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:

/sbin/snmp-ups - from package: nut

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

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