qrsh: 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/qrsh - from package: gridengine
/usr/share/gridengine/bin/lx26-amd64/qrsh - from package: gridengine
/usr/share/gridengine/bin/lx26-x86/qrsh - from package: gridengine

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

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