fastaclean: 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/fastaclean - from package: exonerate

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

On Debian possible default full paths are:

/usr/bin/fastaclean - from package: exonerate

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

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