mergelogs: 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/mergelogs - from package: pen

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

On Debian possible default full paths are:

/usr/bin/mergelogs - from package: pen

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

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