rec: 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/rec - from package: sox

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

On Debian possible default full paths are:

/usr/bin/rec - from package: sox

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

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