slrn_getdescs: 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/sbin/slrn_getdescs - from package: slrn

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

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