collectl: 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 CentOS possible default full paths are:

/usr/bin/collectl - from package: collectl

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/collectl - from package: collectl

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

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