crfreq: 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/crfreq - from package: Canna

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

On Debian possible default full paths are:

/usr/bin/crfreq - from package: Canna

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

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