clsync: 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/clsync - from package: clsync

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