xsm: 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/xsm - from package: x11-session-utils

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