col3: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/col3 - from package: byobu

You may install the required package with command apt-get install {package}
Error in other languages:
col3: bevel nie gevind nie
col3: comandă negăsită
col3: comando não encontrado
col3: commande introuvable
col3: command not found
col3: käsku ei ole
col3: không tìm thấy lệnh
col3: komanda nerasta
col3: Kommando nicht gefunden.
col3: kommandot finns inte
col3: komut yok
col3: nie znaleziono polecenia
col3: níor aimsíodh an t-ordú
col3: no se encontró la orden
col3: no s'ha trobat l'ordre
col3: opdracht niet gevonden
col3: parancs nem található
col3: perintah tidak ditemukan
col3: príkaz nenájdený
col3: příkaz nenalezen
col3: команда не найдена
col3: командата не е открита
col3: 命令找不到
col3: コマンドが見つかりません