blast_formatter: 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/bin/blast_formatter - from package: ncbi-blast+

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

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