nview: 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 CentOS possible default full paths are:

/usr/bin/nview - from package: nvi

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/nview - from package: nvi

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

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