psensor: 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 Debian possible default full paths are:

/usr/bin/psensor - from package: psensor

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

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