qsub: 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/qsub - from package: gridengine
/usr/share/gridengine/bin/lx26-x86/qsub - from package: gridengine

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

On Debian possible default full paths are:

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

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

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