exifgrep: 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/exifgrep - from package: exifprobe

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

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