dirvish-expire: 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/sbin/dirvish-expire - from package: dirvish

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