rpmdev-checksig: 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/bin/rpmdev-checksig - from package: rpmdevtools

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

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