exiv2: 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/exiv2 - from package: exiv2

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

On Debian possible default full paths are:

/usr/bin/exiv2 - from package: exiv2

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

Error in other languages:
exiv2: bevel nie gevind nie
exiv2: comandă negăsită
exiv2: comando não encontrado
exiv2: commande introuvable
exiv2: command not found
exiv2: käsku ei ole
exiv2: không tìm thấy lệnh
exiv2: komanda nerasta
exiv2: Kommando nicht gefunden.
exiv2: kommandot finns inte
exiv2: komut yok
exiv2: nie znaleziono polecenia
exiv2: níor aimsíodh an t-ordú
exiv2: no se encontró la orden
exiv2: no s'ha trobat l'ordre
exiv2: opdracht niet gevonden
exiv2: parancs nem található
exiv2: perintah tidak ditemukan
exiv2: príkaz nenájdený
exiv2: příkaz nenalezen
exiv2: команда не найдена
exiv2: командата не е открита
exiv2: 命令找不到
exiv2: コマンドが見つかりません