FastaUnique: 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/FastaUnique - from package: ampliconnoise

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