clingo: 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/clingo - from package: gringo

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

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