nigiri: command not found

Have You tried accessing the binary with the full path?

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/nigiri - from package: nigiri

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