chattr: 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/chattr - from package: e2fsprogs

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

On Debian possible default full paths are:

/usr/bin/chattr - from package: e2fsprogs

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

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