gjh: 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/lib64/mp/bin/gjh - from package: mp
/usr/lib/mp/bin/gjh - from package: mp

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

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