fastasubseq: 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/fastasubseq - from package: exonerate

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

On Debian possible default full paths are:

/usr/bin/fastasubseq - from package: exonerate

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

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