random_dna.pl: 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/share/gbrowse/htdocs/tutorial/bin/random_dna.pl - from package: gbrowse

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

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