pvresize: 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/pvresize - from package: lvm2

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

On Debian possible default full paths are:

/sbin/pvresize - from package: lvm2

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

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