peg: 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/peg - from package: peg

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