php-cgi: 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/php-cgi - from package: php54w-cli
/usr/bin/php-cgi - from package: php55w-cli
/usr/bin/php-cgi - from package: php56w-cli
/usr/bin/php-cgi - from package: php70w-cli
/usr/bin/php-cgi - from package: php-cli

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

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