ifinfo: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/ifinfo - from package: ctsim

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