qgis.g.browser: 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/lib64/qgis/grass/bin/qgis.g.browser - from package: qgis-grass
/usr/lib/qgis/grass/bin/qgis.g.browser - from package: qgis-grass

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

On Debian possible default full paths are:

/usr/lib/qgis/grass/bin/qgis.g.browser - from package: qgis-plugin-grass

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

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