guilt-select: 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/guilt-select - from package: guilt

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

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