legacy.sh: 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/share/ncbi-blast+/bin/legacy.sh - from package: ncbi-blast+-legacy

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

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