merger: 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 Debian possible default full paths are:

/usr/bin/merger - from package: emboss

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

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