opal-restart: 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 Debian possible default full paths are:

/usr/bin/opal-restart - from package: openmpi-checkpoint

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

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