fastx_nucleotide_distribution_graph.sh: 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_nucleotide_distribution_graph.sh - from package: fastx-toolkit

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