sdrmend: 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 Debian possible default full paths are:

/usr/bin/sdrmend - from package: ion

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

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