pshell3: 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/pshell3 - from package: python3-pyramid

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

Error in other languages:
pshell3: bevel nie gevind nie
pshell3: comandă negăsită
pshell3: comando não encontrado
pshell3: commande introuvable
pshell3: command not found
pshell3: käsku ei ole
pshell3: không tìm thấy lệnh
pshell3: komanda nerasta
pshell3: Kommando nicht gefunden.
pshell3: kommandot finns inte
pshell3: komut yok
pshell3: nie znaleziono polecenia
pshell3: níor aimsíodh an t-ordú
pshell3: no se encontró la orden
pshell3: no s'ha trobat l'ordre
pshell3: opdracht niet gevonden
pshell3: parancs nem található
pshell3: perintah tidak ditemukan
pshell3: príkaz nenájdený
pshell3: příkaz nenalezen
pshell3: команда не найдена
pshell3: командата не е открита
pshell3: 命令找不到
pshell3: コマンドが見つかりません