f95: 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/f95 - from package: gcc-gfortran

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

Error in other languages:
f95: bevel nie gevind nie
f95: comandă negăsită
f95: comando não encontrado
f95: commande introuvable
f95: command not found
f95: käsku ei ole
f95: không tìm thấy lệnh
f95: komanda nerasta
f95: Kommando nicht gefunden.
f95: kommandot finns inte
f95: komut yok
f95: nie znaleziono polecenia
f95: níor aimsíodh an t-ordú
f95: no se encontró la orden
f95: no s'ha trobat l'ordre
f95: opdracht niet gevonden
f95: parancs nem található
f95: perintah tidak ditemukan
f95: príkaz nenájdený
f95: příkaz nenalezen
f95: команда не найдена
f95: командата не е открита
f95: 命令找不到
f95: コマンドが見つかりません