astman: 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/astman - from package: asterisk

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

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