a68g: 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/a68g - from package: algol68g

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

Error in other languages:
a68g: bevel nie gevind nie
a68g: comandă negăsită
a68g: comando não encontrado
a68g: commande introuvable
a68g: command not found
a68g: käsku ei ole
a68g: không tìm thấy lệnh
a68g: komanda nerasta
a68g: Kommando nicht gefunden.
a68g: kommandot finns inte
a68g: komut yok
a68g: nie znaleziono polecenia
a68g: níor aimsíodh an t-ordú
a68g: no se encontró la orden
a68g: no s'ha trobat l'ordre
a68g: opdracht niet gevonden
a68g: parancs nem található
a68g: perintah tidak ditemukan
a68g: príkaz nenájdený
a68g: příkaz nenalezen
a68g: команда не найдена
a68g: командата не е открита
a68g: 命令找不到
a68g: コマンドが見つかりません