petit: 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 CentOS possible default full paths are:

/usr/bin/petit - from package: petit

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/petit - from package: petit

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

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