lsh: 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/lsh - from package: lsh-client

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

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