upscmd: 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/upscmd - from package: nut-client

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

On Debian possible default full paths are:

/bin/upscmd - from package: nut-client

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

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