col1: 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/col1 - from package: byobu

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

Error in other languages:
col1: bevel nie gevind nie
col1: comandă negăsită
col1: comando não encontrado
col1: commande introuvable
col1: command not found
col1: käsku ei ole
col1: không tìm thấy lệnh
col1: komanda nerasta
col1: Kommando nicht gefunden.
col1: kommandot finns inte
col1: komut yok
col1: nie znaleziono polecenia
col1: níor aimsíodh an t-ordú
col1: no se encontró la orden
col1: no s'ha trobat l'ordre
col1: opdracht niet gevonden
col1: parancs nem található
col1: perintah tidak ditemukan
col1: príkaz nenájdený
col1: příkaz nenalezen
col1: команда не найдена
col1: командата не е открита
col1: 命令找不到
col1: コマンドが見つかりません