gslp: 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/gslp - from package: ghostscript

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

On Debian possible default full paths are:

/usr/bin/gslp - from package: ghostscript

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

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