dhcpcd5: 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:

/sbin/dhcpcd5 - from package: dhcpcd5

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

Error in other languages:
dhcpcd5: bevel nie gevind nie
dhcpcd5: comandă negăsită
dhcpcd5: comando não encontrado
dhcpcd5: commande introuvable
dhcpcd5: command not found
dhcpcd5: käsku ei ole
dhcpcd5: không tìm thấy lệnh
dhcpcd5: komanda nerasta
dhcpcd5: Kommando nicht gefunden.
dhcpcd5: kommandot finns inte
dhcpcd5: komut yok
dhcpcd5: nie znaleziono polecenia
dhcpcd5: níor aimsíodh an t-ordú
dhcpcd5: no se encontró la orden
dhcpcd5: no s'ha trobat l'ordre
dhcpcd5: opdracht niet gevonden
dhcpcd5: parancs nem található
dhcpcd5: perintah tidak ditemukan
dhcpcd5: príkaz nenájdený
dhcpcd5: příkaz nenalezen
dhcpcd5: команда не найдена
dhcpcd5: командата не е открита
dhcpcd5: 命令找不到
dhcpcd5: コマンドが見つかりません