geary: 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/geary - from package: geary

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

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