gift-generate-inverted-file: 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/gift-generate-inverted-file - from package: gnuift

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

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