combinediff: 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/combinediff - from package: patchutils

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

On Debian possible default full paths are:

/usr/bin/combinediff - from package: patchutils

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

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