gradle: 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 Debian possible default full paths are:

/usr/bin/gradle - from package: gradle
/usr/share/gradle/bin/gradle - from package: gradle

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

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