dinifti: 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:

/usr/bin/dinifti - from package: dicomnifti

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

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