p7sign: 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/p7sign - from package: libnss3-tools

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

Error in other languages:
p7sign: bevel nie gevind nie
p7sign: comandă negăsită
p7sign: comando não encontrado
p7sign: commande introuvable
p7sign: command not found
p7sign: käsku ei ole
p7sign: không tìm thấy lệnh
p7sign: komanda nerasta
p7sign: Kommando nicht gefunden.
p7sign: kommandot finns inte
p7sign: komut yok
p7sign: nie znaleziono polecenia
p7sign: níor aimsíodh an t-ordú
p7sign: no se encontró la orden
p7sign: no s'ha trobat l'ordre
p7sign: opdracht niet gevonden
p7sign: parancs nem található
p7sign: perintah tidak ditemukan
p7sign: príkaz nenájdený
p7sign: příkaz nenalezen
p7sign: команда не найдена
p7sign: командата не е открита
p7sign: 命令找不到
p7sign: コマンドが見つかりません