spec2spectacle: command not found

Have You tried accessing the binary with the full path?

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/spec2spectacle - from package: spectacle

You may install the required package with command apt-get install {package}
Error in other languages:
spec2spectacle: bevel nie gevind nie
spec2spectacle: comandă negăsită
spec2spectacle: comando não encontrado
spec2spectacle: commande introuvable
spec2spectacle: command not found
spec2spectacle: käsku ei ole
spec2spectacle: không tìm thấy lệnh
spec2spectacle: komanda nerasta
spec2spectacle: Kommando nicht gefunden.
spec2spectacle: kommandot finns inte
spec2spectacle: komut yok
spec2spectacle: nie znaleziono polecenia
spec2spectacle: níor aimsíodh an t-ordú
spec2spectacle: no se encontró la orden
spec2spectacle: no s'ha trobat l'ordre
spec2spectacle: opdracht niet gevonden
spec2spectacle: parancs nem található
spec2spectacle: perintah tidak ditemukan
spec2spectacle: príkaz nenájdený
spec2spectacle: příkaz nenalezen
spec2spectacle: команда не найдена
spec2spectacle: командата не е открита
spec2spectacle: 命令找不到
spec2spectacle: コマンドが見つかりません