eog: 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 CentOS possible default full paths are:

/usr/bin/eog - from package: eog

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/eog - from package: eog

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

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