guilt-branch: command not found

Have You tried accessing the binary with the full path?

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-branch - from package: guilt

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