webcam: 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/webcam - from package: xawtv

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

On Debian possible default full paths are:

/usr/bin/webcam - from package: webcam

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

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