berkeley-abc: 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/berkeley-abc - from package: berkeley-abc

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

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