pidof: 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:

/sbin/pidof - from package: sysvinit-tools

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

On Debian possible default full paths are:

/bin/pidof - from package: sysvinit-utils

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

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