nawk: 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/nawk - from package: nawk

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

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