guvcview: 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/guvcview - from package: guvcview

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

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