pry: 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/pry - from package: pry

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

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