galternatives: 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/galternatives - from package: galternatives
/usr/sbin/galternatives - from package: galternatives

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