fs_mark: 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/fs_mark - from package: fs_mark

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

On Debian possible default full paths are:

/usr/bin/fs_mark - from package: fsmark

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

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