praliases: 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/praliases - from package: sendmail

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

On Debian possible default full paths are:

/usr/sbin/praliases - from package: sendmail-bin

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

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