rstream: 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/rstream - from package: librdmacm-utils

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

On Debian possible default full paths are:

/usr/bin/rstream - from package: rdmacm-utils

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

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