logtail2: 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/sbin/logtail2 - from package: logcheck

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

On Debian possible default full paths are:

/usr/sbin/logtail2 - from package: logtail

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

Error in other languages:
logtail2: bevel nie gevind nie
logtail2: comandă negăsită
logtail2: comando não encontrado
logtail2: commande introuvable
logtail2: command not found
logtail2: käsku ei ole
logtail2: không tìm thấy lệnh
logtail2: komanda nerasta
logtail2: Kommando nicht gefunden.
logtail2: kommandot finns inte
logtail2: komut yok
logtail2: nie znaleziono polecenia
logtail2: níor aimsíodh an t-ordú
logtail2: no se encontró la orden
logtail2: no s'ha trobat l'ordre
logtail2: opdracht niet gevonden
logtail2: parancs nem található
logtail2: perintah tidak ditemukan
logtail2: príkaz nenájdený
logtail2: příkaz nenalezen
logtail2: команда не найдена
logtail2: командата не е открита
logtail2: 命令找不到
logtail2: コマンドが見つかりません