i2cget: 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/sbin/i2cget - from package: i2c-tools

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

On Debian possible default full paths are:

/usr/sbin/i2cget - from package: i2c-tools

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

Error in other languages:
i2cget: bevel nie gevind nie
i2cget: comandă negăsită
i2cget: comando não encontrado
i2cget: commande introuvable
i2cget: command not found
i2cget: käsku ei ole
i2cget: không tìm thấy lệnh
i2cget: komanda nerasta
i2cget: Kommando nicht gefunden.
i2cget: kommandot finns inte
i2cget: komut yok
i2cget: nie znaleziono polecenia
i2cget: níor aimsíodh an t-ordú
i2cget: no se encontró la orden
i2cget: no s'ha trobat l'ordre
i2cget: opdracht niet gevonden
i2cget: parancs nem található
i2cget: perintah tidak ditemukan
i2cget: príkaz nenájdený
i2cget: příkaz nenalezen
i2cget: команда не найдена
i2cget: командата не е открита
i2cget: 命令找不到
i2cget: コマンドが見つかりません