geximon: 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/geximon - from package: geximon

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