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

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

On Debian possible default full paths are:

/usr/bin/qrls - from package: slurm-wlm-torque

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

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