devnag: 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/devnag - from package: texlive-binaries

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

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