runsvdir-start: 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/sbin/runsvdir-start - from package: runit

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

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