safe_finger: 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/sbin/safe_finger - from package: tcp_wrappers

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

On Debian possible default full paths are:

/usr/sbin/safe_finger - from package: tcpd

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

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