grib_ls: 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/grib_ls - from package: grib_api

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

On Debian possible default full paths are:

/usr/bin/grib_ls - from package: libgrib-api-tools

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

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