col2: 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/col2 - from package: byobu

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

Error in other languages:
col2: bevel nie gevind nie
col2: comandă negăsită
col2: comando não encontrado
col2: commande introuvable
col2: command not found
col2: käsku ei ole
col2: không tìm thấy lệnh
col2: komanda nerasta
col2: Kommando nicht gefunden.
col2: kommandot finns inte
col2: komut yok
col2: nie znaleziono polecenia
col2: níor aimsíodh an t-ordú
col2: no se encontró la orden
col2: no s'ha trobat l'ordre
col2: opdracht niet gevonden
col2: parancs nem található
col2: perintah tidak ditemukan
col2: príkaz nenájdený
col2: příkaz nenalezen
col2: команда не найдена
col2: командата не е открита
col2: 命令找不到
col2: コマンドが見つかりません