fedmsg-gateway: 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/fedmsg-gateway - from package: fedmsg-gateway

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

On Debian possible default full paths are:

/usr/bin/fedmsg-gateway - from package: fedmsg-gateway

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

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