psresize: 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/psresize - from package: psutils

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

On Debian possible default full paths are:

/usr/bin/psresize - from package: psutils

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

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