nf2csv: 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/nf2csv - from package: psad

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

On Debian possible default full paths are:

/usr/bin/nf2csv - from package: psad

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

Error in other languages:
nf2csv: bevel nie gevind nie
nf2csv: comandă negăsită
nf2csv: comando não encontrado
nf2csv: commande introuvable
nf2csv: command not found
nf2csv: käsku ei ole
nf2csv: không tìm thấy lệnh
nf2csv: komanda nerasta
nf2csv: Kommando nicht gefunden.
nf2csv: kommandot finns inte
nf2csv: komut yok
nf2csv: nie znaleziono polecenia
nf2csv: níor aimsíodh an t-ordú
nf2csv: no se encontró la orden
nf2csv: no s'ha trobat l'ordre
nf2csv: opdracht niet gevonden
nf2csv: parancs nem található
nf2csv: perintah tidak ditemukan
nf2csv: príkaz nenájdený
nf2csv: příkaz nenalezen
nf2csv: команда не найдена
nf2csv: командата не е открита
nf2csv: 命令找不到
nf2csv: コマンドが見つかりません