requestsync: command not found

Have You tried accessing the binary with the full path?

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/requestsync - from package: ubuntu-dev-tools

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