etckeeper: 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/etckeeper - from package: etckeeper

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

On Debian possible default full paths are:

/usr/bin/etckeeper - from package: etckeeper

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

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