debsigs-installer: 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/debsigs-installer - from package: debsigs

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

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