jigsum: 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/jigsum - from package: jigit

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

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