trev: 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/trev - from package: staden
/usr/lib/staden/bin/trev - from package: staden

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

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