lckdo: 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/lckdo - from package: moreutils

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

On Debian possible default full paths are:

/usr/bin/lckdo - from package: moreutils

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

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