datalog: 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/datalog - from package: datalog

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

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