bitly: 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/bitly - from package: python-bitlyapi

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

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