slideshow: 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/slideshow - from package: batik-slideshow

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

On Debian possible default full paths are:

/usr/bin/slideshow - from package: racket

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

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