pesign-client: 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/pesign-client - from package: pesign

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

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