tracker-search: 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/tracker-search - from package: tracker-utils

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

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