dump.f2fs: 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 Debian possible default full paths are:

/sbin/dump.f2fs - from package: f2fs-tools

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

Error in other languages:
dump.f2fs: bevel nie gevind nie
dump.f2fs: comandă negăsită
dump.f2fs: comando não encontrado
dump.f2fs: commande introuvable
dump.f2fs: command not found
dump.f2fs: käsku ei ole
dump.f2fs: không tìm thấy lệnh
dump.f2fs: komanda nerasta
dump.f2fs: Kommando nicht gefunden.
dump.f2fs: kommandot finns inte
dump.f2fs: komut yok
dump.f2fs: nie znaleziono polecenia
dump.f2fs: níor aimsíodh an t-ordú
dump.f2fs: no se encontró la orden
dump.f2fs: no s'ha trobat l'ordre
dump.f2fs: opdracht niet gevonden
dump.f2fs: parancs nem található
dump.f2fs: perintah tidak ditemukan
dump.f2fs: príkaz nenájdený
dump.f2fs: příkaz nenalezen
dump.f2fs: команда не найдена
dump.f2fs: командата не е открита
dump.f2fs: 命令找不到
dump.f2fs: コマンドが見つかりません