ifetch: 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 Debian possible default full paths are:

/usr/bin/ifetch - from package: ifetch-tools

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

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