viewsudo: 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/viewsudo - from package: umview

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

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