uhd_rx_cfile: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/uhd_rx_cfile - from package: gnuradio

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