mace4: 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/mace4 - from package: prover9

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

Error in other languages:
mace4: bevel nie gevind nie
mace4: comandă negăsită
mace4: comando não encontrado
mace4: commande introuvable
mace4: command not found
mace4: käsku ei ole
mace4: không tìm thấy lệnh
mace4: komanda nerasta
mace4: Kommando nicht gefunden.
mace4: kommandot finns inte
mace4: komut yok
mace4: nie znaleziono polecenia
mace4: níor aimsíodh an t-ordú
mace4: no se encontró la orden
mace4: no s'ha trobat l'ordre
mace4: opdracht niet gevonden
mace4: parancs nem található
mace4: perintah tidak ditemukan
mace4: príkaz nenájdený
mace4: příkaz nenalezen
mace4: команда не найдена
mace4: командата не е открита
mace4: 命令找不到
mace4: コマンドが見つかりません