chfn: 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/chfn - from package: util-linux-ng

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

On Debian possible default full paths are:

/usr/bin/chfn - from package: passwd

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

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