cvmsh2: 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/cvmsh2 - from package: freefem++

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

Error in other languages:
cvmsh2: bevel nie gevind nie
cvmsh2: comandă negăsită
cvmsh2: comando não encontrado
cvmsh2: commande introuvable
cvmsh2: command not found
cvmsh2: käsku ei ole
cvmsh2: không tìm thấy lệnh
cvmsh2: komanda nerasta
cvmsh2: Kommando nicht gefunden.
cvmsh2: kommandot finns inte
cvmsh2: komut yok
cvmsh2: nie znaleziono polecenia
cvmsh2: níor aimsíodh an t-ordú
cvmsh2: no se encontró la orden
cvmsh2: no s'ha trobat l'ordre
cvmsh2: opdracht niet gevonden
cvmsh2: parancs nem található
cvmsh2: perintah tidak ditemukan
cvmsh2: príkaz nenájdený
cvmsh2: příkaz nenalezen
cvmsh2: команда не найдена
cvmsh2: командата не е открита
cvmsh2: 命令找不到
cvmsh2: コマンドが見つかりません