supervise: 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

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/supervise - from package: daemontools

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