rigctld: 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/rigctld - from package: hamlib

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

On Debian possible default full paths are:

/usr/bin/rigctld - from package: libhamlib-utils

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

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