gifflip: 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/gifflip - from package: giflib-utils

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

On Debian possible default full paths are:

/usr/bin/gifflip - from package: giflib-tools

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

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