logserial: 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/logserial - from package: logserial

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

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