pil: 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/pil - from package: picolisp

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