print_sum: 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/print_sum - from package: sloccount

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

On Debian possible default full paths are:

/usr/bin/print_sum - from package: sloccount

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

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