fastx_barcode_splitter.pl: command not found

Have You tried accessing the binary with the full path?

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/fastx_barcode_splitter.pl - from package: fastx-toolkit

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