chrt: 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/chrt - from package: util-linux-ng

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

On Debian possible default full paths are:

/usr/bin/chrt - from package: util-linux

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

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