itksnap: 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/itksnap - from package: itksnap

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

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