macs2diff: 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/macs2diff - from package: macs

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

Error in other languages:
macs2diff: bevel nie gevind nie
macs2diff: comandă negăsită
macs2diff: comando não encontrado
macs2diff: commande introuvable
macs2diff: command not found
macs2diff: käsku ei ole
macs2diff: không tìm thấy lệnh
macs2diff: komanda nerasta
macs2diff: Kommando nicht gefunden.
macs2diff: kommandot finns inte
macs2diff: komut yok
macs2diff: nie znaleziono polecenia
macs2diff: níor aimsíodh an t-ordú
macs2diff: no se encontró la orden
macs2diff: no s'ha trobat l'ordre
macs2diff: opdracht niet gevonden
macs2diff: parancs nem található
macs2diff: perintah tidak ditemukan
macs2diff: príkaz nenájdený
macs2diff: příkaz nenalezen
macs2diff: команда не найдена
macs2diff: командата не е открита
macs2diff: 命令找不到
macs2diff: コマンドが見つかりません