sha224sum: 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/sha224sum - from package: coreutils

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

On Debian possible default full paths are:

/usr/bin/sha224sum - from package: coreutils

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

Error in other languages:
sha224sum: bevel nie gevind nie
sha224sum: comandă negăsită
sha224sum: comando não encontrado
sha224sum: commande introuvable
sha224sum: command not found
sha224sum: käsku ei ole
sha224sum: không tìm thấy lệnh
sha224sum: komanda nerasta
sha224sum: Kommando nicht gefunden.
sha224sum: kommandot finns inte
sha224sum: komut yok
sha224sum: nie znaleziono polecenia
sha224sum: níor aimsíodh an t-ordú
sha224sum: no se encontró la orden
sha224sum: no s'ha trobat l'ordre
sha224sum: opdracht niet gevonden
sha224sum: parancs nem található
sha224sum: perintah tidak ditemukan
sha224sum: príkaz nenájdený
sha224sum: příkaz nenalezen
sha224sum: команда не найдена
sha224sum: командата не е открита
sha224sum: 命令找不到
sha224sum: コマンドが見つかりません