jardiff: 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/jardiff - from package: jardiff

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

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