psbook: 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/psbook - from package: psutils

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

On Debian possible default full paths are:

/usr/bin/psbook - from package: psutils

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

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