pmc: 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/sbin/pmc - from package: linuxptp

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

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